### 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
AnnotationNode *last_annotation = annotation_stack.back()->get();
		if (last_annotation->applies_to(p_target)) {
			annotations.push_front(last_annotation);
			annotation_stack.pop_back();
		} else {
			push_error(vformat(R"(Annotation "%s" cannot be applied to a %s.)", last_annotation->name, p_member_kind));
			clear_unused_annotations();
		}
#ifdef TOOLS_ENABLED
		if (last_annotation->start_line == doc_comment_line) {
			doc_comment_line--;
		}
#endif 
	}
	T *member = (this->*p_parse_function)(p_is_static);
	if (member == nullptr) {
		return;
	}
	for (AnnotationNode *&annotation : annotations) {
		member->annotations.push_back(annotation);
	}
#ifdef TOOLS_ENABLED
	
	class_doc_line = MIN(class_doc_line, doc_comment_line - 1);
	
	if (has_comment(previous.start_line, true)) {
		member->doc_description = get_doc_comment(previous.start_line, true);
	} else if (has_comment(doc_comment_line, true)) {
		if constexpr (std::is_same_v<T, ClassNode>) {
			get_class_doc_comment(doc_comment_line, member->doc_brief_description, member->doc_description, member->doc_tutorials, true);