overlays: remove 'nvim-treesitter-legacy-shim'

With the migration complete, I do not need it anymore.

This reverts commit bf260de243.

modules/home/vim/plugin/settings/tree-sitter.lua

@@ -74,19 +74,21 @@ local function treesitter_try_attach(buf, language)
     -- Syntax highlighting
     vim.treesitter.start(buf, language)
     -- Indentation
-    vim.bo.indentexpr = "v:lua.require'nvim-treesitter'.indentexpr()"
+    vim.bo.indentexpr = "v:lua.require('nvim-treesitter').indentexpr()"
 
     return true
 end
 
 vim.api.nvim_create_autocmd("FileType", {
+    pattern = "*",
+    group = vim.api.nvim_create_augroup("treesitter_attach", { clear = true }),
     callback = function(args)
         local buf, filetype = args.buf, args.match
-        local lang = vim.treesitter.language.get_lang(filetype)
+        local language = vim.treesitter.language.get_lang(filetype)
         if not language then
             return
         end
-        treesitter_try_attach(buf, lang)
+        treesitter_try_attach(buf, language)
     end,
 })
 
@@ -95,6 +97,8 @@ vim.api.nvim_create_autocmd("FileType", {
 local installable_parsers = require("nvim-treesitter").get_available()
 
 vim.api.nvim_create_autocmd("FileType", {
+    pattern = "*",
+    group = vim.api.nvim_create_augroup("treesitter_attach", { clear = true }),
     callback = function(args)
         local buf, filetype = args.buf, args.match
         local language = vim.treesitter.language.get_lang(filetype)
@@ -102,7 +106,7 @@ vim.api.nvim_create_autocmd("FileType", {
             return
         end
 
-        if not treesitter_try_attach(buf,language) then
+        if not treesitter_try_attach(buf, language) then
             if vim.tbl_contains(installable_parsers, language) then
                 -- Not already installed, so try to install them via nvim-treesitter if possible
                 require("nvim-treesitter").install(language):await(function()