fix: align identifiers to query.c parser logic

Namely, they cannot have `$`, but they can contain `?` or `!`

https://github.com/tree-sitter/tree-sitter/blob/4339b0fe05b264082bd159a77b21fc5d586c3a29/lib/src/query.c#L403C1-L418C2

Author: ribru17

grammar.js

@@ -10,8 +10,8 @@ const PREC = {
   WILDCARD_NODE: 1,
 };
 
-// Identifiers cannot start with `.`
-const IDENTIFIER = /[a-zA-Z0-9\-_\$][a-zA-Z0-9.\-_\$]*/;
+// Identifiers cannot start with `.`, `?`, or `!`
+const IDENTIFIER = /[a-zA-Z0-9\-_][a-zA-Z0-9.\-_?!]*/;
 
 module.exports = grammar({
   name: "query",