Followup improvements to LSP (#11430)

Addressing things brought up in https://github.com/neovim/neovim/issues/11389 and beyond.

- Bugfix for empty dictionary serialization.
- Reduce markdown previews of code.
- Refactor method triggers to `lsp.buf.*` methods
- Switch to v:lua and get rid of vim interface.
- Get rid of filetype config in favor of something from https://github.com/neovim/nvim-lsp
- Switch error messages to something which doesn't require `ENTER` because if an LSP goes crazy, it'll block neovim.
- Rename `builtin_callbacks` to `default_callbacks`
- Resolve callback at time of calling using default_callbacks instead of at client creation
- Make hover/signatureHelp preview focusable so you can mess with it.
- Add vim.lsp.util.set_qflist and vim.lsp.util.set_loclist and vim.lsp.util.locations_to_items().
- Add apply_textedit and tests which enables a new class of features.
- Fix column offsets in character and bytes in vim.lsp.buf to be correct.

New methods:
- Add textDocument/references under vim.lsp.buf.references()
- Finish textDocument/rename
- Finish textDocument/rangeFormatting and textDocument/format

1 files changed, 19 insertions, 12 deletions

diff --git a/runtime/lua/vim/shared.lua b/runtime/lua/vim/shared.lua
index 6aa5f3bd9b..1912d3708d 100644
--- a/runtime/lua/vim/shared.lua
+++ b/runtime/lua/vim/shared.lua
@@ -226,18 +226,25 @@ function vim.tbl_add_reverse_lookup(o)
   return o
 end
 
---- Extends a list-like table with the values of another list-like table.
----
---NOTE: This *mutates* dst!
---@see |extend()|
----
---@param dst The list which will be modified and appended to.
---@param src The list from which values will be inserted.
-function vim.list_extend(dst, src)
-  assert(type(dst) == 'table', "dst must be a table")
-  assert(type(src) == 'table', "src must be a table")
-  for _, v in ipairs(src) do
-    table.insert(dst, v)
+-- Extends a list-like table with the values of another list-like table.
+--
+-- NOTE: This *mutates* dst!
+-- @see |extend()|
+--
+-- @param dst list which will be modified and appended to.
+-- @param src list from which values will be inserted.
+-- @param start Start index on src. defaults to 1
+-- @param finish Final index on src. defaults to #src
+-- @returns dst
+function vim.list_extend(dst, src, start, finish)
+  vim.validate {
+    dst = {dst, 't'};
+    src = {src, 't'};
+    start = {start, 'n', true};
+    finish = {finish, 'n', true};
+  }
+  for i = start or 1, finish or #src do
+    table.insert(dst, src[i])
   end
   return dst
 end