### 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
ERR_FAIL_COND_V_MSG(p_target->type != Node::CLASS, false, vformat(R"("%s" annotation can only be applied to classes.)", p_annotation->name));
	ClassNode *p_class = static_cast<ClassNode *>(p_target);
	if (p_class->annotated_static_unload) {
		push_error(vformat(R"("%s" annotation can only be used once per script.)", p_annotation->name), p_annotation);
		return false;
	}
	p_class->annotated_static_unload = true;
	return true;
}
GDScriptParser::DataType GDScriptParser::SuiteNode::Local::get_datatype() const {
	switch (type) {
		case CONSTANT:
			return constant->get_datatype();
		case VARIABLE:
			return variable->get_datatype();
		case PARAMETER:
			return parameter->get_datatype();
		case FOR_VARIABLE:
		case PATTERN_BIND:
			return bind->get_datatype();
		case UNDEFINED:
			return DataType();
	}
	return DataType();
}
String GDScriptParser::SuiteNode::Local::get_name() const {