### 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
clear();
	String source = p_source_code;
	int cursor_line = -1;
	int cursor_column = -1;
	for_completion = p_for_completion;
	int tab_size = 4;
#ifdef TOOLS_ENABLED
	if (EditorSettings::get_singleton()) {
		tab_size = EditorSettings::get_singleton()->get_setting("text_editor/behavior/indent/size");
	}
#endif 
	if (p_for_completion) {
		
		const Vector<String> lines = p_source_code.split("\n");
		cursor_line = 1;
		cursor_column = 1;
		for (int i = 0; i < lines.size(); i++) {
			bool found = false;
			const String &line = lines[i];
			for (int j = 0; j < line.size(); j++) {
				if (line[j] == char32_t(0xFFFF)) {
					found = true;
					break;
				} else if (line[j] == '\t') {
					cursor_column += tab_size - 1;
				}
				cursor_column++;
			}