### 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"(Expected expression as the function argument.)");
		} else {
			call->arguments.push_back(argument);
			if (argument->type == Node::IDENTIFIER && use_identifier_completion) {
				completion_context.type = COMPLETION_IDENTIFIER;
			}
		}
		ct = COMPLETION_CALL_ARGUMENTS;
	} while (match(GDScriptTokenizer::Token::COMMA));
	pop_completion_call();
	pop_multiline();
	consume(GDScriptTokenizer::Token::PARENTHESIS_CLOSE, R"*(Expected closing ")" after call arguments.)*");
	complete_extents(call);
	return call;
}
GDScriptParser::ExpressionNode *GDScriptParser::parse_get_node(ExpressionNode *p_previous_operand, bool p_can_assign) {
	if (!current.is_node_name() && !check(GDScriptTokenizer::Token::LITERAL) && !check(GDScriptTokenizer::Token::SLASH) && !check(GDScriptTokenizer::Token::PERCENT)) {
		push_error(vformat(R"(Expected node path as string or identifier after "%s".)", previous.get_name()));
		return nullptr;
	}
	if (check(GDScriptTokenizer::Token::LITERAL)) {
		if (current.literal.get_type() != Variant::STRING) {
			push_error(vformat(R"(Expected node path as string or identifier after "%s".)", previous.get_name()));
			return nullptr;
		}
	}
	GetNodeNode *get_node = alloc_node<GetNodeNode>();
	
	
	enum PathState {