feat(treesitter): add filetype -> lang API

Problem:

  vim.treesitter does not know how to map a specific filetype to a parser.

  This creates problems since in a few places (including in vim.treesitter itself), the filetype is incorrectly used in place of lang.

Solution:

  Add an API to enable this:

  - Add vim.treesitter.language.add() as a replacement for vim.treesitter.language.require_language().
    - Optional arguments are now passed via an opts table.
    - Also takes a filetype (or list of filetypes) so we can keep track of what filetypes are associated with which langs.
    - Deprecated vim.treesitter.language.require_language().
  - Add vim.treesitter.language.get_lang() which returns the associated lang for a given filetype.
  - Add vim.treesitter.language.register() to associate filetypes to a lang without loading the parser.

1 files changed, 1 insertions, 1 deletions

diff --git a/runtime/lua/vim/treesitter/health.lua b/runtime/lua/vim/treesitter/health.lua
index c0a1eca0ce..1abcdd0b31 100644
--- a/runtime/lua/vim/treesitter/health.lua
+++ b/runtime/lua/vim/treesitter/health.lua
@@ -17,7 +17,7 @@ function M.check()
 
   for _, parser in pairs(parsers) do
     local parsername = vim.fn.fnamemodify(parser, ':t:r')
-    local is_loadable, ret = pcall(ts.language.require_language, parsername)
+    local is_loadable, ret = pcall(ts.language.add, parsername)
 
     if not is_loadable or not ret then
       health.report_error(