### 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
int begin_scan = String("@tutorial").length();
			if (begin_scan >= stripped_line.length()) {
				continue; 
			}
			if (stripped_line[begin_scan] == ':') { 
				
				title = "";
				link = stripped_line.trim_prefix("@tutorial:").strip_edges();
			} else {
				/* Syntax:
				 *   @tutorial ( The Title Here )         :         https://the.url/
				 *             ^ open           ^ close   ^ colon   ^ url
				 */
				int open_bracket_pos = begin_scan, close_bracket_pos = 0;
				while (open_bracket_pos < stripped_line.length() && (stripped_line[open_bracket_pos] == ' ' || stripped_line[open_bracket_pos] == '\t')) {
					open_bracket_pos++;
				}
				if (open_bracket_pos == stripped_line.length() || stripped_line[open_bracket_pos++] != '(') {
					continue; 
				}
				close_bracket_pos = open_bracket_pos;
				while (close_bracket_pos < stripped_line.length() && stripped_line[close_bracket_pos] != ')') {
					close_bracket_pos++;
				}
				if (close_bracket_pos == stripped_line.length()) {
					continue; 
				}
				int colon_pos = close_bracket_pos + 1;
				while (colon_pos < stripped_line.length() && (stripped_line[colon_pos] == ' ' || stripped_line[colon_pos] == '\t')) {
					colon_pos++;