### 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
switch (mode) {
			case BRIEF:
				p_brief += _process_doc_line(doc_line, p_brief, space_prefix, state);
				break;
			case DESC:
				p_desc += _process_doc_line(doc_line, p_desc, space_prefix, state);
				break;
			case TUTORIALS:
				p_tutorials.append(Pair<String, String>(title, link));
				break;
			case DONE:
				break;
		}
	}
	if (current_class->members.size() > 0) {
		const ClassNode::Member &m = current_class->members[0];
		int first_member_line = m.get_line();
		if (first_member_line == line) {
			p_brief = "";
			p_desc = "";
			p_tutorials.clear();
		}
	}
}
#endif 
GDScriptParser::ParseRule *GDScriptParser::get_rule(GDScriptTokenizer::Token::Type p_token_type) {
	
	
	
	static ParseRule rules[] = {