### 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
builtin_types.clear();
}
void GDScriptParser::get_annotation_list(List<MethodInfo> *r_annotations) const {
	for (const KeyValue<StringName, AnnotationInfo> &E : valid_annotations) {
		r_annotations->push_back(E.value.info);
	}
}
bool GDScriptParser::annotation_exists(const String &p_annotation_name) const {
	return valid_annotations.has(p_annotation_name);
}
GDScriptParser::GDScriptParser() {
	
	
	register_annotation(MethodInfo("@tool"), AnnotationInfo::SCRIPT, &GDScriptParser::tool_annotation);
	register_annotation(MethodInfo("@icon", PropertyInfo(Variant::STRING, "icon_path")), AnnotationInfo::SCRIPT, &GDScriptParser::icon_annotation);
	register_annotation(MethodInfo("@static_unload"), AnnotationInfo::SCRIPT, &GDScriptParser::static_unload_annotation);
	register_annotation(MethodInfo("@onready"), AnnotationInfo::VARIABLE, &GDScriptParser::onready_annotation);
	
	register_annotation(MethodInfo("@export"), AnnotationInfo::VARIABLE, &GDScriptParser::export_annotations<PROPERTY_HINT_NONE, Variant::NIL>);
	register_annotation(MethodInfo("@export_enum", PropertyInfo(Variant::STRING, "names")), AnnotationInfo::VARIABLE, &GDScriptParser::export_annotations<PROPERTY_HINT_ENUM, Variant::NIL>, varray(), true);
	register_annotation(MethodInfo("@export_file", PropertyInfo(Variant::STRING, "filter")), AnnotationInfo::VARIABLE, &GDScriptParser::export_annotations<PROPERTY_HINT_FILE, Variant::STRING>, varray(""), true);