### 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

‮
GDScriptTokenizer::Token::Type op_type = previous.type;
	UnaryOpNode *operation = alloc_node<UnaryOpNode>();
	switch (op_type) {
		case GDScriptTokenizer::Token::MINUS:
			operation->operation = UnaryOpNode::OP_NEGATIVE;
			operation->variant_op = Variant::OP_NEGATE;
			operation->operand = parse_precedence(PREC_SIGN, false);
			if (operation->operand == nullptr) {
				push_error(R"(Expected expression after "-" operator.)");
			}
			break;
		case GDScriptTokenizer::Token::PLUS:
			operation->operation = UnaryOpNode::OP_POSITIVE;
			operation->variant_op = Variant::OP_POSITIVE;