feat: added numbered list to the slash menu

frontend/app_flowy/packages/appflowy_editor/lib/src/render/selection_menu/selection_menu_service.dart

@@ -169,6 +169,14 @@ final List<SelectionMenuItem> _defaultSelectionMenuItems = [
       insertBulletedListAfterSelection(editorState);
     },
   ),
+  SelectionMenuItem(
+    name: () => AppFlowyEditorLocalizations.current.numberedList,
+    icon: _selectionMenuIcon('number'),
+    keywords: ['numbered list', 'list', 'ordered list'],
+    handler: (editorState, _, __) {
+      insertNumberedListAfterSelection(editorState);
+    },
+  ),
   SelectionMenuItem(
     name: () => AppFlowyEditorLocalizations.current.checkbox,
     icon: _selectionMenuIcon('checkbox'),

frontend/app_flowy/packages/appflowy_editor/lib/src/service/default_text_operations/format_rich_text_style.dart

@@ -34,6 +34,13 @@ void insertBulletedListAfterSelection(EditorState editorState) {
   });
 }
 
+void insertNumberedListAfterSelection(EditorState editorState) {
+  insertTextNodeAfterSelection(editorState, {
+    BuiltInAttributeKey.subtype: BuiltInAttributeKey.numberList,
+    BuiltInAttributeKey.number: 1,
+  });
+}
+
 bool insertTextNodeAfterSelection(
     EditorState editorState, Attributes attributes) {
   final selection = editorState.service.selectionService.currentSelection.value;