fix(runtime): source old color scheme in bundled color schemes (#26641)

Problem:
Bundled color schemes use `:hi clear` and only define Vim's highlight
groups. This results into Nvim-specific highlight groups using
definitions from Nvim's default color scheme, which are not always
linked to a Vim's highlight group.

Solution:
Restore links to Vim's highlight groups which were present before Nvim's
default color scheme update.

26 files changed, 53 insertions, 27 deletions

diff --git a/runtime/colors/blue.vim b/runtime/colors/blue.vim
index f0009d1000..2d0e48f448 100644
--- a/runtime/colors/blue.vim
+++ b/runtime/colors/blue.vim
@@ -10,7 +10,8 @@
 
 set background=dark
 
-hi clear
+" hi clear
+source $VIMRUNTIME/colors/vim.lua " Nvim: revert to Vim default color scheme
 let g:colors_name = 'blue'
 
 let s:t_Co = &t_Co
diff --git a/runtime/colors/darkblue.vim b/runtime/colors/darkblue.vim
index ec8d03ed22..05b3fa4199 100644
--- a/runtime/colors/darkblue.vim
+++ b/runtime/colors/darkblue.vim
@@ -10,7 +10,8 @@
 
 set background=dark
 
-hi clear
+" hi clear
+source $VIMRUNTIME/colors/vim.lua " Nvim: revert to Vim default color scheme
 let g:colors_name = 'darkblue'
 
 let s:t_Co = &t_Co
diff --git a/runtime/colors/delek.vim b/runtime/colors/delek.vim
index e8152e3e39..1919526760 100644
--- a/runtime/colors/delek.vim
+++ b/runtime/colors/delek.vim
@@ -10,7 +10,8 @@
 
 set background=light
 
-hi clear
+" hi clear
+source $VIMRUNTIME/colors/vim.lua " Nvim: revert to Vim default color scheme
 let g:colors_name = 'delek'
 
 let s:t_Co = &t_Co
diff --git a/runtime/colors/desert.vim b/runtime/colors/desert.vim
index 627394df3e..453e966899 100644
--- a/runtime/colors/desert.vim
+++ b/runtime/colors/desert.vim
@@ -10,7 +10,8 @@
 
 set background=dark
 
-hi clear
+" hi clear
+source $VIMRUNTIME/colors/vim.lua " Nvim: revert to Vim default color scheme
 let g:colors_name = 'desert'
 
 let s:t_Co = &t_Co
diff --git a/runtime/colors/elflord.vim b/runtime/colors/elflord.vim
index 4808f1158f..001368861f 100644
--- a/runtime/colors/elflord.vim
+++ b/runtime/colors/elflord.vim
@@ -9,7 +9,8 @@
 
 set background=dark
 
-hi clear
+" hi clear
+source $VIMRUNTIME/colors/vim.lua " Nvim: revert to Vim default color scheme
 let g:colors_name = 'elflord'
 
 let s:t_Co = &t_Co
diff --git a/runtime/colors/evening.vim b/runtime/colors/evening.vim
index fd689461f0..01fc0d8354 100644
--- a/runtime/colors/evening.vim
+++ b/runtime/colors/evening.vim
@@ -10,7 +10,8 @@
 
 set background=dark
 
-hi clear
+" hi clear
+source $VIMRUNTIME/colors/vim.lua " Nvim: revert to Vim default color scheme
 let g:colors_name = 'evening'
 
 let s:t_Co = &t_Co
diff --git a/runtime/colors/habamax.vim b/runtime/colors/habamax.vim
index fd372b9e73..1073ba3d93 100644
--- a/runtime/colors/habamax.vim
+++ b/runtime/colors/habamax.vim
@@ -10,7 +10,8 @@
 
 set background=dark
 
-hi clear
+" hi clear
+source $VIMRUNTIME/colors/vim.lua " Nvim: revert to Vim default color scheme
 let g:colors_name = 'habamax'
 
 let s:t_Co = &t_Co
diff --git a/runtime/colors/industry.vim b/runtime/colors/industry.vim
index 28d410be65..449bf3b676 100644
--- a/runtime/colors/industry.vim
+++ b/runtime/colors/industry.vim
@@ -10,7 +10,8 @@
 
 set background=dark
 
-hi clear
+" hi clear
+source $VIMRUNTIME/colors/vim.lua " Nvim: revert to Vim default color scheme
 let g:colors_name = 'industry'
 
 let s:t_Co = &t_Co
diff --git a/runtime/colors/koehler.vim b/runtime/colors/koehler.vim
index c1eb425d7e..8a63f91a94 100644
--- a/runtime/colors/koehler.vim
+++ b/runtime/colors/koehler.vim
@@ -9,7 +9,8 @@
 
 set background=dark
 
-hi clear
+" hi clear
+source $VIMRUNTIME/colors/vim.lua " Nvim: revert to Vim default color scheme
 let g:colors_name = 'koehler'
 
 let s:t_Co = &t_Co
diff --git a/runtime/colors/lunaperche.vim b/runtime/colors/lunaperche.vim
index e9a4e8ecf6..3c8682737e 100644
--- a/runtime/colors/lunaperche.vim
+++ b/runtime/colors/lunaperche.vim
@@ -8,7 +8,8 @@
 
 " Generated by Colortemplate v2.2.3
 
-hi clear
+" hi clear
+source $VIMRUNTIME/colors/vim.lua " Nvim: revert to Vim default color scheme
 let g:colors_name = 'lunaperche'
 
 let s:t_Co = &t_Co
diff --git a/runtime/colors/morning.vim b/runtime/colors/morning.vim
index def4f9ef65..12f1efe9a6 100644
--- a/runtime/colors/morning.vim
+++ b/runtime/colors/morning.vim
@@ -10,7 +10,8 @@
 
 set background=light
 
-hi clear
+" hi clear
+source $VIMRUNTIME/colors/vim.lua " Nvim: revert to Vim default color scheme
 let g:colors_name = 'morning'
 
 let s:t_Co = &t_Co
diff --git a/runtime/colors/murphy.vim b/runtime/colors/murphy.vim
index 434fafc058..66b994a6c7 100644
--- a/runtime/colors/murphy.vim
+++ b/runtime/colors/murphy.vim
@@ -10,7 +10,8 @@
 
 set background=dark
 
-hi clear
+" hi clear
+source $VIMRUNTIME/colors/vim.lua " Nvim: revert to Vim default color scheme
 let g:colors_name = 'murphy'
 
 let s:t_Co = &t_Co
diff --git a/runtime/colors/pablo.vim b/runtime/colors/pablo.vim
index b4335eedec..f53739bc6d 100644
--- a/runtime/colors/pablo.vim
+++ b/runtime/colors/pablo.vim
@@ -9,7 +9,8 @@
 
 set background=dark
 
-hi clear
+" hi clear
+source $VIMRUNTIME/colors/vim.lua " Nvim: revert to Vim default color scheme
 let g:colors_name = 'pablo'
 
 let s:t_Co = &t_Co
diff --git a/runtime/colors/peachpuff.vim b/runtime/colors/peachpuff.vim
index 3ae756f682..f4c1e21697 100644
--- a/runtime/colors/peachpuff.vim
+++ b/runtime/colors/peachpuff.vim
@@ -10,7 +10,8 @@
 
 set background=light
 
-hi clear
+" hi clear
+source $VIMRUNTIME/colors/vim.lua " Nvim: revert to Vim default color scheme
 let g:colors_name = 'peachpuff'
 
 let s:t_Co = &t_Co
diff --git a/runtime/colors/quiet.vim b/runtime/colors/quiet.vim
index 52d49ba258..d7f8582888 100644
--- a/runtime/colors/quiet.vim
+++ b/runtime/colors/quiet.vim
@@ -8,7 +8,8 @@
 
 " Generated by Colortemplate v2.2.3
 
-hi clear
+" hi clear
+source $VIMRUNTIME/colors/vim.lua " Nvim: revert to Vim default color scheme
 let g:colors_name = 'quiet'
 
 let s:t_Co = &t_Co
diff --git a/runtime/colors/retrobox.vim b/runtime/colors/retrobox.vim
index f9d8d329e4..b4a194d885 100644
--- a/runtime/colors/retrobox.vim
+++ b/runtime/colors/retrobox.vim
@@ -8,7 +8,8 @@
 
 " Generated by Colortemplate v2.2.3
 
-hi clear
+" hi clear
+source $VIMRUNTIME/colors/vim.lua " Nvim: revert to Vim default color scheme
 let g:colors_name = 'retrobox'
 
 let s:t_Co = &t_Co
diff --git a/runtime/colors/ron.vim b/runtime/colors/ron.vim
index 1ea8d71143..4d55f9978f 100644
--- a/runtime/colors/ron.vim
+++ b/runtime/colors/ron.vim
@@ -9,7 +9,8 @@
 
 set background=dark
 
-hi clear
+" hi clear
+source $VIMRUNTIME/colors/vim.lua " Nvim: revert to Vim default color scheme
 let g:colors_name = 'ron'
 
 let s:t_Co = &t_Co
diff --git a/runtime/colors/shine.vim b/runtime/colors/shine.vim
index 4e2e4bc3d9..b4a8793589 100644
--- a/runtime/colors/shine.vim
+++ b/runtime/colors/shine.vim
@@ -10,7 +10,8 @@
 
 set background=light
 
-hi clear
+" hi clear
+source $VIMRUNTIME/colors/vim.lua " Nvim: revert to Vim default color scheme
 let g:colors_name = 'shine'
 
 let s:t_Co = &t_Co
diff --git a/runtime/colors/slate.vim b/runtime/colors/slate.vim
index 225a845de3..aab6208b26 100644
--- a/runtime/colors/slate.vim
+++ b/runtime/colors/slate.vim
@@ -10,7 +10,8 @@
 
 set background=dark
 
-hi clear
+" hi clear
+source $VIMRUNTIME/colors/vim.lua " Nvim: revert to Vim default color scheme
 let g:colors_name = 'slate'
 
 let s:t_Co = &t_Co
diff --git a/runtime/colors/sorbet.vim b/runtime/colors/sorbet.vim
index 77e2223dca..e4ef42469c 100644
--- a/runtime/colors/sorbet.vim
+++ b/runtime/colors/sorbet.vim
@@ -10,7 +10,8 @@
 
 set background=dark
 
-hi clear
+" hi clear
+source $VIMRUNTIME/colors/vim.lua " Nvim: revert to Vim default color scheme
 let g:colors_name = 'sorbet'
 
 let s:t_Co = &t_Co
diff --git a/runtime/colors/torte.vim b/runtime/colors/torte.vim
index bcba7258da..36da28e596 100644
--- a/runtime/colors/torte.vim
+++ b/runtime/colors/torte.vim
@@ -10,7 +10,8 @@
 
 set background=dark
 
-hi clear
+" hi clear
+source $VIMRUNTIME/colors/vim.lua " Nvim: revert to Vim default color scheme
 let g:colors_name = 'torte'
 
 let s:t_Co = &t_Co
diff --git a/runtime/colors/wildcharm.vim b/runtime/colors/wildcharm.vim
index f41e5379f0..ae0489e259 100644
--- a/runtime/colors/wildcharm.vim
+++ b/runtime/colors/wildcharm.vim
@@ -8,7 +8,8 @@
 
 " Generated by Colortemplate v2.2.3
 
-hi clear
+" hi clear
+source $VIMRUNTIME/colors/vim.lua " Nvim: revert to Vim default color scheme
 let g:colors_name = 'wildcharm'
 
 let s:t_Co = &t_Co
diff --git a/runtime/colors/zaibatsu.vim b/runtime/colors/zaibatsu.vim
index 50c5122989..726843345b 100644
--- a/runtime/colors/zaibatsu.vim
+++ b/runtime/colors/zaibatsu.vim
@@ -10,7 +10,8 @@
 
 set background=dark
 
-hi clear
+" hi clear
+source $VIMRUNTIME/colors/vim.lua " Nvim: revert to Vim default color scheme
 let g:colors_name = 'zaibatsu'
 
 let s:t_Co = &t_Co
diff --git a/runtime/colors/zellner.vim b/runtime/colors/zellner.vim
index a998033566..37f012e92d 100644
--- a/runtime/colors/zellner.vim
+++ b/runtime/colors/zellner.vim
@@ -10,7 +10,8 @@
 
 set background=light
 
-hi clear
+" hi clear
+source $VIMRUNTIME/colors/vim.lua " Nvim: revert to Vim default color scheme
 let g:colors_name = 'zellner'
 
 let s:t_Co = &t_Co
diff --git a/runtime/doc/news.txt b/runtime/doc/news.txt
index f8d1dea78f..b85cbe7b95 100644
--- a/runtime/doc/news.txt
+++ b/runtime/doc/news.txt
@@ -106,7 +106,8 @@ The following changes may require adaptations in user config or plugins.
   This also might result into some color schemes looking differently due to
   them relying on an implicit assumptions about how highlight groups are
   defined by default. To account for this, define all attributes of highlight
-  groups explicitly or use `:colorscheme vim` to restore previous definitions.
+  groups explicitly. Alternatively, use `:colorscheme vim` or
+  `:source $VIMRUNTIME/colors/vim.lua` to restore previous definitions.
 
 • 'termguicolors' is enabled by default when Nvim is able to determine that
   the host terminal emulator supports 24-bit color.
diff --git a/runtime/doc/vim_diff.txt b/runtime/doc/vim_diff.txt
index ca260246fc..0552689860 100644
--- a/runtime/doc/vim_diff.txt
+++ b/runtime/doc/vim_diff.txt
@@ -32,8 +32,9 @@ Defaults					            *nvim-defaults*
   ":syntax off" to |init.vim|.
 - Default color scheme has been updated. This can result in color schemes
   looking differently due to them relying on how highlight groups are defined
-  by default. Add ":colorscheme vim" to |init.vim| or your color scheme file to
-  restore the old default links and colors.
+  by default. Add ":colorscheme vim" to |init.vim| or
+  ":source $VIMRUNTIME/colors/vim.lua" to your color scheme file to restore
+  the old default links and colors.
 
 - 'autoindent' is enabled
 - 'autoread' is enabled (works in all UIs, including terminal)