### Godot version

3b086aa06

### System information

ArchLinux x11

### Issue description

```gdscript
extends Node

@export_group("My Properties")
@export var number = 3
@export var string = ""

@export_group("Prefixed Properties", "prefix_")
@export var prefix_number = 3
@export var prefix_string = ""

@export_group("", "")
@export var ungrouped_number = 3
```

![image](https://user-images.githubusercontent.com/70787919/214983963-528c415b-745b-47fc-9777-36ebe31a3060.png)


### Steps to reproduce

- create script
- @export_group
- go inspector

### Minimal reproduction project

‮
int argument_index = 0;
			do {
				make_completion_context(COMPLETION_ANNOTATION_ARGUMENTS, annotation, argument_index, true);
				set_last_completion_call_arg(argument_index++);
				ExpressionNode *argument = parse_expression(false);
				if (argument == nullptr) {
					valid = false;
					continue;
				}
				annotation->arguments.push_back(argument);
			} while (match(GDScriptTokenizer::Token::COMMA));
			pop_multiline();
			consume(GDScriptTokenizer::Token::PARENTHESIS_CLOSE, R"*(Expected ")" after annotation arguments.)*");
		}
		pop_completion_call();
	}
	complete_extents(annotation);
	match(GDScriptTokenizer::Token::NEWLINE); 
	if (valid) {
		valid = validate_annotation_argument_count(annotation);
	}
	return valid ? annotation : nullptr;
}
void GDScriptParser::clear_unused_annotations() {
	for (const AnnotationNode *annotation : annotation_stack) {
		push_error(vformat(R"(Annotation "%s" does not precedes a valid target, so it will have no effect.)", annotation->name), annotation);
	}
	annotation_stack.clear();
}
bool GDScriptParser::register_annotation(const MethodInfo &p_info, uint32_t p_target_kinds, AnnotationAction p_apply, const Vector<Variant> &p_default_arguments, bool p_is_vararg) {