### 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
}
	return true;
}
template <PropertyUsageFlags t_usage>
bool GDScriptParser::export_group_annotations(const AnnotationNode *p_annotation, Node *p_node) {
	AnnotationNode *annotation = const_cast<AnnotationNode *>(p_annotation);
	if (annotation->resolved_arguments.is_empty()) {
		return false;
	}
	annotation->export_info.name = annotation->resolved_arguments[0];
	switch (t_usage) {
		case PROPERTY_USAGE_CATEGORY: {
			annotation->export_info.usage = t_usage;
		} break;
		case PROPERTY_USAGE_GROUP: {
			annotation->export_info.usage = t_usage;
			if (annotation->resolved_arguments.size() == 2) {
				annotation->export_info.hint_string = annotation->resolved_arguments[1];
			}
		} break;
		case PROPERTY_USAGE_SUBGROUP: {
			annotation->export_info.usage = t_usage;
			if (annotation->resolved_arguments.size() == 2) {
				annotation->export_info.hint_string = annotation->resolved_arguments[1];
			}
		} break;
	}
	return true;
}
bool GDScriptParser::warning_annotations(const AnnotationNode *p_annotation, Node *p_node) {