### 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
for (const AnnotationNode *E : p_function->annotations) {
		print_annotation(E);
	}
	push_text(p_context);
	push_text(" ");
	if (p_function->identifier) {
		print_identifier(p_function->identifier);
	} else {
		push_text("<anonymous>");
	}
	push_text("( ");
	for (int i = 0; i < p_function->parameters.size(); i++) {
		if (i > 0) {
			push_text(" , ");
		}
		print_parameter(p_function->parameters[i]);
	}
	push_line(" ) :");
	increase_indent();
	print_suite(p_function->body);
	decrease_indent();
}
void GDScriptParser::TreePrinter::print_get_node(GetNodeNode *p_get_node) {