### 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
break;
		case Node::RETURN:
			print_return(static_cast<ReturnNode *>(p_statement));
			break;
		case Node::BREAK:
			push_line("Break");
			break;
		case Node::CONTINUE:
			push_line("Continue");
			break;
		case Node::PASS:
			push_line("Pass");
			break;
		case Node::BREAKPOINT:
			push_line("Breakpoint");
			break;
		case Node::ASSIGNMENT:
			print_assignment(static_cast<AssignmentNode *>(p_statement));
			break;
		default:
			if (p_statement->is_expression()) {
				print_expression(static_cast<ExpressionNode *>(p_statement));
				push_line();
			} else {
				push_line(vformat("<unknown statement %d>", p_statement->type));
			}
			break;
	}
}
void GDScriptParser::TreePrinter::print_suite(SuiteNode *p_suite) {