### 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
return static_cast<LiteralNode *>(parse_literal(nullptr, false));
}
GDScriptParser::ExpressionNode *GDScriptParser::parse_literal(ExpressionNode *p_previous_operand, bool p_can_assign) {
	if (previous.type != GDScriptTokenizer::Token::LITERAL) {
		push_error("Parser bug: parsing literal node without literal token.");
		ERR_FAIL_V_MSG(nullptr, "Parser bug: parsing literal node without literal token.");
	}
	LiteralNode *literal = alloc_node<LiteralNode>();
	complete_extents(literal);
	literal->value = previous.literal;
	return literal;
}
GDScriptParser::ExpressionNode *GDScriptParser::parse_self(ExpressionNode *p_previous_operand, bool p_can_assign) {
	if (current_function && current_function->is_static) {
		push_error(R"(Cannot use "self" inside a static function.)");
	}
	SelfNode *self = alloc_node<SelfNode>();
	complete_extents(self);
	self->current_class = current_class;
	return self;
}
GDScriptParser::ExpressionNode *GDScriptParser::parse_builtin_constant(ExpressionNode *p_previous_operand, bool p_can_assign) {