### 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 
_stop_thread();
	MutexLock data_lock(data_mutex);
	ERR_FAIL_COND(current->type == ITEM_TABLE);
	ItemStrikethrough *item = memnew(ItemStrikethrough);
	_add_item(item, true);
}
void RichTextLabel::push_paragraph(HorizontalAlignment p_alignment, Control::TextDirection p_direction, const String &p_language, TextServer::StructuredTextParser p_st_parser, BitField<TextServer::JustificationFlag> p_jst_flags, const PackedFloat32Array &p_tab_stops) {
	_stop_thread();
	MutexLock data_lock(data_mutex);
	ERR_FAIL_COND(current->type == ITEM_TABLE);
	ItemParagraph *item = memnew(ItemParagraph);
	item->alignment = p_alignment;
	item->direction = p_direction;
	item->language = p_language;
	item->st_parser = p_st_parser;
	item->jst_flags = p_jst_flags;
	item->tab_stops = p_tab_stops;
	_add_item(item, true, true);
}
void RichTextLabel::push_indent(int p_level) {
	_stop_thread();
	MutexLock data_lock(data_mutex);
	ERR_FAIL_COND(current->type == ITEM_TABLE);
	ERR_FAIL_COND(p_level < 0);
	ItemIndent *item = memnew(ItemIndent);
	item->level = p_level;
	_add_item(item, true, true);
}
void RichTextLabel::push_list(int p_level, ListType p_list, bool p_capitalize, const String &p_bullet) {