### Godot version

4.0 stable

### System information

Fedora, RX 590

### Issue description

I made a dictionary, and instead of using `:` to separate between key and value, i accidentally used `=`.
The error message was not clear at all `Parse Error: Expected identifier or string as LUA-style dictionary key.` 

I don't think assuming that people know how dictionaries are made in LUA is reasonable. And if this is not about LUA the programming language, i don't even know what this is about :D

I think this error should be replaced with something of the sort "Please use `:` as separator instead of `=` in your dictionary"

### Steps to reproduce

Paste this code in a script:

```

var dict = {
	1 = "lala"
}
```

Observe the error message
![image](https://user-images.githubusercontent.com/7917475/224549538-38ea25aa-ba75-431e-868b-0733a53b90ad.png)


### Minimal reproduction project

see above
}
	parse_class_body(true);
	complete_extents(head);
#ifdef TOOLS_ENABLED
	for (const KeyValue<int, GDScriptTokenizer::CommentData> &E : tokenizer.get_comments()) {
		if (E.value.new_line && E.value.comment.begins_with("##")) {
			class_doc_line = MIN(class_doc_line, E.key);
		}
	}
	if (has_comment(class_doc_line)) {
		get_class_doc_comment(class_doc_line, head->doc_brief_description, head->doc_description, head->doc_tutorials, false);
	}
#endif 
	if (!check(GDScriptTokenizer::Token::TK_EOF)) {
		push_error("Expected end of file.");
	}
	clear_unused_annotations();
}
GDScriptParser::ClassNode *GDScriptParser::find_class(const String &p_qualified_name) const {
	String first = p_qualified_name.get_slice("::", 0);
	Vector<String> class_names;
	GDScriptParser::ClassNode *result = nullptr;
	
	if (first.is_empty() || (head->identifier && first == head->identifier->name)) {
		class_names = p_qualified_name.split("::");
		result = head;
	} else if (p_qualified_name.begins_with(script_path)) {
		
		class_names = p_qualified_name.trim_prefix(script_path).split("::");
		result = head;