### 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
if (locals_indices.has(p_name)) {
		return true;
	}
	if (parent_block != nullptr) {
		return parent_block->has_local(p_name);
	}
	return false;
}
const GDScriptParser::SuiteNode::Local &GDScriptParser::SuiteNode::get_local(const StringName &p_name) const {
	if (locals_indices.has(p_name)) {
		return locals[locals_indices[p_name]];
	}
	if (parent_block != nullptr) {
		return parent_block->get_local(p_name);
	}
	return empty;
}
bool GDScriptParser::AnnotationNode::apply(GDScriptParser *p_this, Node *p_target) {
	if (is_applied) {
		return true;
	}
	is_applied = true;
	return (p_this->*(p_this->valid_annotations[name].apply))(this, p_target);
}
bool GDScriptParser::AnnotationNode::applies_to(uint32_t p_target_kinds) const {
	return (info->target_kind & p_target_kinds) > 0;
}
bool GDScriptParser::validate_annotation_arguments(AnnotationNode *p_annotation) {