nvim: treesitter: Disable additional vim regex highlighting

With this set to true, neovim will run `:h syntax` and tree-sitter
at the same time. Using this option may slow down one's editor and
one may see some duplicate highlights. Disable it.

nvim/.config/nvim/lua/treesitter.lua

@@ -3,7 +3,10 @@ local ts_langs = { "bash", "cpp", "diff", "fennel", "fish", "go", "haskell", "ht
 require'nvim-treesitter.install'.compilers = { "gcc" }
 require'nvim-treesitter.configs'.setup {
   ensure_installed = ts_langs,
-  highlight        = { enable = true, },
+  highlight        = {
+    enable = true,
+    additional_vim_regex_highlighting = false,
+  },
   query_linter = {
     enable           = true,
     use_virtual_text = true,