feat: add parser for ocaml interface files

The files have the mli extension. The parser grammar uses the name
ocaml_interface, but since vim the underscore has a special meaning
ocamlinterface is used as the filetype.

lua/nvim-treesitter/parsers.lua

@@ -135,6 +135,16 @@ list.ocaml = {
   maintainers = {'@undu'},
 }
 
+list.ocaml_interface = {
+  install_info = {
+    url = "https://github.com/tree-sitter/tree-sitter-ocaml",
+    files = { "src/parser.c", "src/scanner.cc" },
+    location = "tree-sitter-ocaml_interface/interface"
+  },
+  maintainers = {'@undu'},
+  filetype = 'ocamlinterface'
+}
+
 list.swift = {
   install_info = {
     url = "https://github.com/tree-sitter/tree-sitter-swift",

lua/nvim-treesitter/query.lua

@@ -15,6 +15,7 @@ M.base_language_map = {
   typescript = {'javascript'},
   javascript = {'jsx'},
   tsx = {'typescript', 'javascript', 'jsx'},
+  ocaml_interface = {'ocaml'},
 }
 
 M.built_in_query_groups = {'highlights', 'locals', 'textobjects', 'folds'}