chore: refactor parser.rs (#6896)

Breaking up one of the larger functions into some smaller pieces to make it a bit more manageable

## Checklist

- [ ] Title matches [Winglang's style guide](https://www.winglang.io/contributing/start-here/pull_requests#how-are-pull-request-titles-formatted)
- [ ] Description explains motivation and solution
- [ ] Tests added (always)
- [ ] Docs updated (only required for features)
- [ ] Added `pr/e2e-full` label if this feature requires end-to-end testing

*By submitting this pull request, I confirm that my contribution is made under the terms of the [Wing Cloud Contribution License](https://github.com/winglang/wing/blob/main/CONTRIBUTION_LICENSE.md)*.

libs/tree-sitter-wing/grammar.js

@@ -21,7 +21,7 @@ const PREC = {
 module.exports = grammar({
   name: "wing",
 
-  extras: ($) => [$.comment, $.doc, /[\s\p{Zs}\uFEFF\u2060\u200B]/],
+  extras: ($) => [$.comment, $.doc, /[\s\p{Zs}\uFEFF\u2060\u200B]/u],
 
   word: ($) => $.identifier,
 

libs/tree-sitter-wing/jsconfig.json

@@ -2,7 +2,8 @@
   "compilerOptions": {
     "checkJs": true,
     "module": "CommonJS",
-    "lib": ["ES2020"]
+    "lib": ["ES2020"],
+    "target": "ES2020"
   },
   "include": ["grammar.js", "tree-sitter-dsl.d.ts"]
 }