### 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 (colon_pos == stripped_line.length() || stripped_line[colon_pos++] != ':') {
					continue; 
				}
				title = stripped_line.substr(open_bracket_pos, close_bracket_pos - open_bracket_pos).strip_edges();
				link = stripped_line.substr(colon_pos).strip_edges();
			}
			mode = TUTORIALS;
			in_codeblock = false;
		} else if (stripped_line.is_empty()) {
			continue;
		} else {
			
			if (mode == TUTORIALS) {
				mode = DONE;
			}
			in_codeblock = _in_codeblock(doc_line, in_codeblock, &codeblock_begins);
		}
		if (in_codeblock) {
			int i = 0;
			for (; i < codeblock_begins; i++) {
				if (doc_line[i] != ' ') {
					break;
				}
			}
			doc_line = doc_line.substr(i);
		} else {
			doc_line = stripped_line;
		}
		String line_join = (in_codeblock) ? "\n" : " ";