### 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
print_expression(p_match_pattern->expression);
			break;
		case PatternNode::PT_ARRAY:
			push_text("[ ");
			for (int i = 0; i < p_match_pattern->array.size(); i++) {
				if (i > 0) {
					push_text(" , ");
				}
				print_match_pattern(p_match_pattern->array[i]);
			}
			push_text(" ]");
			break;
		case PatternNode::PT_DICTIONARY:
			push_text("{ ");
			for (int i = 0; i < p_match_pattern->dictionary.size(); i++) {
				if (i > 0) {
					push_text(" , ");
				}
				if (p_match_pattern->dictionary[i].key != nullptr) {
					
					print_expression(p_match_pattern->dictionary[i].key);
					push_text(" : ");
				}
				print_match_pattern(p_match_pattern->dictionary[i].value_pattern);
			}
			push_text(" }");
			break;
	}
}
void GDScriptParser::TreePrinter::print_parameter(ParameterNode *p_parameter) {