### 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
complete_extents(get_node);
				return nullptr;
			}
			get_node->full_path += "%";
			path_state = PATH_STATE_PERCENT;
		} else if (previous.type == GDScriptTokenizer::Token::SLASH) {
			if (path_state != PATH_STATE_START && path_state != PATH_STATE_NODE_NAME) {
				push_error(R"("/" is only valid at the beginning of the path or after a node name.)");
				complete_extents(get_node);
				return nullptr;
			}
			get_node->full_path += "/";
			path_state = PATH_STATE_SLASH;
		}
		make_completion_context(COMPLETION_GET_NODE, get_node, context_argument++);
		if (match(GDScriptTokenizer::Token::LITERAL)) {
			if (previous.literal.get_type() != Variant::STRING) {
				String previous_token;
				switch (path_state) {
					case PATH_STATE_START:
						previous_token = "$";
						break;
					case PATH_STATE_PERCENT:
						previous_token = "%";
						break;
					case PATH_STATE_SLASH:
						previous_token = "/";
						break;
					default:
						break;