### 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 (p_annotation->name == SNAME("@export_range")) {
		if (export_type.builtin_type == Variant::INT) {
			variable->export_info.type = Variant::INT;
		}
	}
	if (p_annotation->name == SNAME("@export_multiline")) {
		if (export_type.builtin_type == Variant::ARRAY && export_type.has_container_element_type()) {
			DataType inner_type = export_type.get_container_element_type();
			if (inner_type.builtin_type != Variant::STRING) {
				push_error(vformat(R"("%s" annotation on arrays requires a string type but type "%s" was given instead.)", p_annotation->name.operator String(), inner_type.to_string()), variable);
				return false;
			}
			String hint_prefix = itos(inner_type.builtin_type) + "/" + itos(variable->export_info.hint);
			variable->export_info.hint = PROPERTY_HINT_TYPE_STRING;
			variable->export_info.hint_string = hint_prefix + ":" + variable->export_info.hint_string;
			variable->export_info.type = Variant::ARRAY;
			return true;
		} else if (export_type.builtin_type == Variant::DICTIONARY) {
			variable->export_info.type = Variant::DICTIONARY;
			return true;
		} else if (export_type.builtin_type == Variant::PACKED_STRING_ARRAY) {
			String hint_prefix = itos(Variant::STRING) + "/" + itos(variable->export_info.hint);
			variable->export_info.hint = PROPERTY_HINT_TYPE_STRING;
			variable->export_info.hint_string = hint_prefix + ":" + variable->export_info.hint_string;
			variable->export_info.type = Variant::PACKED_STRING_ARRAY;
			return true;
		}
	}
	if (p_annotation->name == SNAME("@export")) {
		if (variable->datatype_specifier == nullptr && variable->initializer == nullptr) {