Add go-mod tree-sitter config

Adds a tree-sitter config for go.mod files as well as highlighting
queries.

lua/nvim-treesitter/parsers.lua

@@ -104,6 +104,16 @@ list.go = {
   maintainers = {"@theHamsta", "@WinWisely268"},
 }
 
+list.gomod = {
+  install_info = {
+    url = "https://github.com/camdencheek/tree-sitter-go-mod",
+	branch = "main",
+    files = { "src/parser.c" },
+  },
+  maintainers = {"@camdencheek"},
+  filetype = "gomod",
+}
+
 list.graphql = {
   install_info = {
     url = "https://github.com/bkegley/tree-sitter-graphql",

queries/gomod/highlights.scm

@@ -0,0 +1,17 @@
+[
+  "require"
+  "replace"
+  "go"
+  "exclude"
+  "retract"
+  "module"
+] @keyword
+
+"=>" @operator
+
+(comment) @comment
+
+[
+(version)
+(go_version)
+] @string