fix(nvim): install Treesitter grammars with Nix

Fixes #48

after/plugin/treesitter.lua

@@ -4,8 +4,6 @@ if not has_configs then
 end
 
 
-local parser_install_dir = vim.fn.stdpath('cache') .. "treesitters";
-
 configs.setup {
   autotag = {
     enable = true,
@@ -13,29 +11,6 @@ configs.setup {
   context_commenting = {
     enable = true,
   },
-  ensure_installed = {
-    "astro",
-    "bash",
-    "comment",
-    "css",
-    "dockerfile",
-    "go",
-    "html",
-    "javascript",
-    "json",
-    "lua",
-    "make",
-    "markdown",
-    "php",
-    "phpdoc",
-    "regex",
-    "rst",
-    "scss",
-    "typescript",
-    "vim",
-    "vue",
-    "yaml",
-  },
   highlight = {
     enable = true,
   },
@@ -59,12 +34,8 @@ configs.setup {
       },
     },
   },
-  parser_install_dir = parser_install_dir,
 }
 
-vim.fn.mkdir(parser_install_dir, "p")
-vim.opt.runtimepath:append(parser_install_dir)
-
 local nmap = require("opdavies.keymap").nmap
 
 nmap { "<leader>th", "<cmd>TSHighlightCapturesUnderCursor<CR>" }