### 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
push_error(R"(Cannot use simple "@export" annotation with variable without type or initializer, since type can't be inferred.)", p_annotation);
			return false;
		}
		bool is_array = false;
		if (export_type.builtin_type == Variant::ARRAY && export_type.has_container_element_type()) {
			export_type = export_type.get_container_element_type(); 
			is_array = true;
		}
		if (export_type.is_variant() || export_type.has_no_type()) {
			push_error(R"(Cannot use simple "@export" annotation because the type of the initialized value can't be inferred.)", p_annotation);
			return false;
		}
		switch (export_type.kind) {
			case GDScriptParser::DataType::BUILTIN:
				variable->export_info.type = export_type.builtin_type;
				variable->export_info.hint = PROPERTY_HINT_NONE;
				variable->export_info.hint_string = Variant::get_type_name(export_type.builtin_type);
				break;
			case GDScriptParser::DataType::NATIVE:
				if (ClassDB::is_parent_class(export_type.native_type, SNAME("Resource"))) {
					variable->export_info.type = Variant::OBJECT;
					variable->export_info.hint = PROPERTY_HINT_RESOURCE_TYPE;
					variable->export_info.hint_string = export_type.native_type;
				} else if (ClassDB::is_parent_class(export_type.native_type, SNAME("Node"))) {
					variable->export_info.type = Variant::OBJECT;
					variable->export_info.hint = PROPERTY_HINT_NODE_TYPE;
					variable->export_info.hint_string = export_type.native_type;
				} else {
					push_error(R"(Export type can only be built-in, a resource, a node, or an enum.)", variable);
					return false;