### Godot version

master ([06ccbfe](https://github.com/godotengine/godot/commit/06ccbfe8eec6e840db3df2360dc2804386f940b8))

### System information

PopOS 22.04

### Issue description

Sometimes the doc page is broken when the engine is closed and then restarted.
Closing the doc and opening it again fixes it.

![2023-05-27_22-15](https://github.com/godotengine/godot/assets/3624853/ed202a55-03e8-420a-bc1c-ccfc7f7cd02a)


### Steps to reproduce

- Open a documentation page for any node
- Restart Godot

### Minimal reproduction project

NA

EDIT : Added the commit hash @Calinou 
ERR_FAIL_COND((int)p_text_direction < -1 || (int)p_text_direction > 3);
	_stop_thread();
	if (text_direction != p_text_direction) {
		text_direction = p_text_direction;
		main->first_invalid_line.store(0); 
		_validate_line_caches();
		queue_redraw();
	}
}
void RichTextLabel::set_structured_text_bidi_override(TextServer::StructuredTextParser p_parser) {