docs(help): specify h4 "function signature" format #42434master

Work towards enabling ["flow" layout](https://github.com/neovim/neovim/blob/9244da12e400ec0291450a5e9400d995e7a29b83/src/gen/gen_help_html.lua#L86-L88)
in all `:help` files.

Problem:
The final boss of vimdoc pseudo-structure: Vim's quasi-headings on
function signatures and excmd docs is visually distinctive but too
inconsistent for a nice parse rule.

Solution:
- Define the quasi-heading format as an "h4" variant, specified at
  `:help help-tag-heading`.
  - For simplicity and predictability, it is defined as any line that
    ends with a help tag(s) preceded by 2 or more spaces (or 1 tab).
- Update existing docs.
  - This one-time update has a lot of changes, but is very unlikely to
    conflict with ported Vim-patches because (1) Vim rarely adds new
    *excmds* that we want, and (2) *function* docs are auto-generated.

ref https://github.com/neovim/tree-sitter-vimdoc/issues/110

1 files changed, 2 insertions, 4 deletions

diff --git a/runtime/doc/mlang.txt b/runtime/doc/mlang.txt
index 1ba149173f..46e373a49d 100644
--- a/runtime/doc/mlang.txt
+++ b/runtime/doc/mlang.txt
@@ -27,8 +27,7 @@ directories (for Unix): >
 Unfortunately, upper/lowercase differences matter.  Also watch out for the
 use of "-" and "_".
 
-					    *:lan* *:lang* *:language* *E197*
-:lan[guage]
+:lan[guage]				*:lan* *:lang* *:language* *E197*
 :lan[guage] mes[sages]
 :lan[guage] cty[pe]
 :lan[guage] tim[e]
@@ -156,8 +155,7 @@ in a Vim script.  For a language that has no translation yet, please consider
 becoming the maintainer and make your translations available to all Vim users.
 Send an e-mail to the Vim maintainer <maintainer@vim.org>.
 
-					*:menut* *:menutrans* *:menutranslate*
-:menut[ranslate] clear
+:menut[ranslate] clear			*:menut* *:menutrans* *:menutranslate*
 			Clear all menu translations.
 
 :menut[ranslate] {english} {mylang}