### 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
return;
	}
	switch (p_expression->type) {
		case Node::ARRAY:
			print_array(static_cast<ArrayNode *>(p_expression));
			break;
		case Node::ASSIGNMENT:
			print_assignment(static_cast<AssignmentNode *>(p_expression));
			break;
		case Node::AWAIT:
			print_await(static_cast<AwaitNode *>(p_expression));
			break;
		case Node::BINARY_OPERATOR:
			print_binary_op(static_cast<BinaryOpNode *>(p_expression));
			break;
		case Node::CALL:
			print_call(static_cast<CallNode *>(p_expression));
			break;
		case Node::CAST:
			print_cast(static_cast<CastNode *>(p_expression));
			break;
		case Node::DICTIONARY:
			print_dictionary(static_cast<DictionaryNode *>(p_expression));
			break;
		case Node::GET_NODE:
			print_get_node(static_cast<GetNodeNode *>(p_expression));
			break;
		case Node::IDENTIFIER:
			print_identifier(static_cast<IdentifierNode *>(p_expression));
			break;