### Godot version

v4.0.beta14.official [28a24639c]

### System information

MacOS 12.6.2

### Issue description

Beta 14 throws an error for custom `@icon`, e.g.
```
class_name StateMachine extends Node

@icon("res://assets/icons/state_machine.svg")
```
> Annotation "`@icon`" is not allowed in this level.

In beta 13 and before that worked fine.

### Steps to reproduce

1. Add a custom `@icon` in a custom node script.
2. Error message: Annotation "`@icon`" is not allowed in this level.

There are possibly other errors because a `class_name` node is now not recognized if extended by other classes, but they should resolve if `@icon` is removed.

### Minimal reproduction project

N/A
if (!for_completion) {
		return;
	}
	CompletionCall call;
	call.call = p_call;
	call.argument = 0;
	completion_call_stack.push_back(call);
	if (previous.cursor_place == GDScriptTokenizer::CURSOR_MIDDLE || previous.cursor_place == GDScriptTokenizer::CURSOR_END || current.cursor_place == GDScriptTokenizer::CURSOR_BEGINNING) {
		completion_call = call;
	}
}
void GDScriptParser::pop_completion_call() {
	if (!for_completion) {
		return;
	}
	ERR_FAIL_COND_MSG(completion_call_stack.is_empty(), "Trying to pop empty completion call stack");
	completion_call_stack.pop_back();
}
void GDScriptParser::set_last_completion_call_arg(int p_argument) {
	if (!for_completion || passed_cursor) {
		return;
	}
	ERR_FAIL_COND_MSG(completion_call_stack.is_empty(), "Trying to set argument on empty completion call stack");
	completion_call_stack.back()->get().argument = p_argument;
}
Error GDScriptParser::parse(const String &p_source_code, const String &p_script_path, bool p_for_completion) {