feat(vlang): initial support

Add support for vlang filetypes.

- [ ] Highlight `C` as builtin variable. This is FFI in vlang land,
  where C act like extern and access c functions. The vlang parser does
  some extension between C function calls and arguments but I believe
  highlighting C as builtin variable is sufficient indicator for now. I
  tried to use offset! but failed. Any suggestions?
- [ ] Set up parser url. the vlang parser is located within [vls] repo. Is
  installing from nested repo supported? `tree_sitter_v/src/parser.c`?

[vls]: https://github.com/vlang/vls/tree/master/tree_sitter_v

cc @elianiva @theHamsta

lua/nvim-treesitter/parsers.lua

@@ -1068,6 +1068,17 @@ list.proto = {
   filetype = "proto",
 }
 
+list.v = {
+  install_info = {
+    url = "~/sources/vls/tree_sitter_v",
+    files = { "src/parser.c", "src/scanner.c" },
+    generate_requires_npm = false,
+    requires_generate_from_grammar = false,
+  },
+  filetype = "vlang",
+  maintainers = { "@tami5" },
+}
+
 local M = {
   list = list,
   filetype_to_parsername = filetype_to_parsername,