### 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 
int64_t n = p_num;
	int chars = 0;
	do {
		n /= 24;
		chars++;
	} while (n);
	String s;
	s.resize(chars + 1);
	char32_t *c = s.ptrw();
	c[chars] = 0;
	n = p_num;
	do {
		int mod = ABS(n % 24);
		char a = (p_capitalize ? 'A' : 'a');
		c[--chars] = a + mod - 1;
		n /= 24;
	} while (n);
	return s;
}
void RichTextLabel::_update_line_font(ItemFrame *p_frame, int p_line, const Ref<Font> &p_base_font, int p_base_font_size) {