chore: remove unused imports

frontend/app_flowy/packages/appflowy_editor/example/lib/plugin/code_block_node_widget.dart

@@ -45,7 +45,7 @@ ShortcutEventHandler _ignorekHandler = (editorState, event) {
 };
 
 SelectionMenuItem codeBlockItem = SelectionMenuItem(
-  name: 'Code Block',
+  name: () => 'Code Block',
   icon: const Icon(Icons.abc),
   keywords: ['code block'],
   handler: (editorState, _, __) {

frontend/app_flowy/packages/appflowy_editor/lib/src/render/rich_text/built_in_text_widget.dart

@@ -1,5 +1,4 @@
 import 'package:appflowy_editor/appflowy_editor.dart';
-import 'package:appflowy_editor/src/render/rich_text/default_selectable.dart';
 import 'package:flutter/material.dart';
 
 abstract class BuiltInTextWidget extends StatefulWidget {

frontend/app_flowy/packages/appflowy_editor/lib/src/service/internal_key_event_handlers/backspace_handler.dart

@@ -3,7 +3,6 @@ import 'package:appflowy_editor/src/service/internal_key_event_handlers/number_l
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:appflowy_editor/appflowy_editor.dart';
-import 'package:appflowy_editor/src/extensions/path_extensions.dart';
 
 // Handle delete text.
 ShortcutEventHandler deleteTextHandler = (editorState, event) {

frontend/app_flowy/packages/appflowy_editor/lib/src/service/internal_key_event_handlers/copy_paste_handler.dart

@@ -1,7 +1,6 @@
 import 'package:appflowy_editor/appflowy_editor.dart';
 import 'package:appflowy_editor/src/infra/html_converter.dart';
 import 'package:appflowy_editor/src/document/node_iterator.dart';
-import 'package:appflowy_editor/src/document/built_in_attribute_keys.dart';
 import 'package:appflowy_editor/src/service/internal_key_event_handlers/number_list_helper.dart';
 import 'package:flutter/material.dart';
 import 'package:rich_clipboard/rich_clipboard.dart';

frontend/app_flowy/packages/appflowy_editor/lib/src/service/internal_key_event_handlers/enter_without_shift_in_text_node_handler.dart

@@ -3,7 +3,6 @@ import 'dart:collection';
 import 'package:appflowy_editor/appflowy_editor.dart';
 import 'package:flutter/material.dart';
 
-import 'package:appflowy_editor/src/extensions/path_extensions.dart';
 import './number_list_helper.dart';
 
 /// Handle some cases where enter is pressed and shift is not pressed.

frontend/app_flowy/packages/appflowy_editor/lib/src/service/internal_key_event_handlers/markdown_syntax_to_styled_text.dart

@@ -1,4 +1,3 @@
-import "dart:math";
 import 'package:appflowy_editor/appflowy_editor.dart';
 import 'package:appflowy_editor/src/extensions/text_node_extensions.dart';
 import 'package:appflowy_editor/src/service/default_text_operations/format_rich_text_style.dart';
@@ -49,7 +48,7 @@ ShortcutEventHandler backquoteToCodeHandler = (editorState, event) {
       .substring(selection.start.offset, selection.end.offset);
 
   // toggle code style when selected some text
-  if (selectionText.length > 0) {
+  if (selectionText.isNotEmpty) {
     formatEmbedCode(editorState);
     return KeyEventResult.handled;
   }

frontend/app_flowy/packages/appflowy_editor/test/extensions/path_extensions_test.dart

@@ -1,6 +1,5 @@
 import 'package:appflowy_editor/appflowy_editor.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:appflowy_editor/src/extensions/path_extensions.dart';
 
 void main() async {
   setUpAll(() {

frontend/app_flowy/packages/appflowy_editor/test/render/rich_text/checkbox_text_test.dart

@@ -1,6 +1,4 @@
 import 'package:appflowy_editor/appflowy_editor.dart';
-import 'package:appflowy_editor/src/document/built_in_attribute_keys.dart';
-import 'package:appflowy_editor/src/render/rich_text/default_selectable.dart';
 import 'package:appflowy_editor/src/extensions/text_node_extensions.dart';
 import 'package:flutter_test/flutter_test.dart';
 import '../../infra/test_editor.dart';

frontend/app_flowy/packages/appflowy_editor/test/render/rich_text/toolbar_rich_text_test.dart

@@ -1,5 +1,4 @@
 import 'package:appflowy_editor/appflowy_editor.dart';
-import 'package:appflowy_editor/src/document/built_in_attribute_keys.dart';
 import 'package:appflowy_editor/src/extensions/text_node_extensions.dart';
 import 'package:appflowy_editor/src/render/toolbar/toolbar_item_widget.dart';
 import 'package:appflowy_editor/src/render/toolbar/toolbar_widget.dart';

frontend/app_flowy/packages/appflowy_editor/test/render/selection_menu/selection_menu_widget_test.dart

@@ -1,7 +1,6 @@
 import 'package:appflowy_editor/appflowy_editor.dart';
 import 'package:appflowy_editor/src/render/selection_menu/selection_menu_item_widget.dart';
 import 'package:appflowy_editor/src/render/selection_menu/selection_menu_service.dart';
-import 'package:appflowy_editor/src/render/selection_menu/selection_menu_widget.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 import '../../infra/test_editor.dart';
@@ -13,8 +12,8 @@ void main() async {
 
   group('selection_menu_widget.dart', () {
     for (var i = 0; i < defaultSelectionMenuItems.length; i += 1) {
-      testWidgets('Selects number.$i item in selection menu with enter', (
-          tester) async {
+      testWidgets('Selects number.$i item in selection menu with enter',
+          (tester) async {
         final editor = await _prepare(tester);
         for (var j = 0; j < i; j++) {
           await editor.pressLogicKey(LogicalKeyboardKey.arrowDown);
@@ -30,8 +29,8 @@ void main() async {
         }
       });
 
-      testWidgets('Selects number.$i item in selection menu with click', (
-          tester) async {
+      testWidgets('Selects number.$i item in selection menu with click',
+          (tester) async {
         final editor = await _prepare(tester);
 
         await tester.tap(find.byType(SelectionMenuItemWidget).at(i));
@@ -148,7 +147,8 @@ Future<void> _testDefaultSelectionMenuItems(
     int index, EditorWidgetTester editor) async {
   expect(editor.documentLength, 4);
   expect(editor.documentSelection, Selection.single(path: [2], startOffset: 0));
-  expect((editor.nodeAtPath([1]) as TextNode).toRawString(), 'Welcome to Appflowy 😁');
+  expect((editor.nodeAtPath([1]) as TextNode).toRawString(),
+      'Welcome to Appflowy 😁');
   final node = editor.nodeAtPath([2]);
   final item = defaultSelectionMenuItems[index];
   final itemName = item.name();

frontend/app_flowy/packages/appflowy_editor/test/service/internal_key_event_handlers/backspace_handler_test.dart

@@ -2,7 +2,6 @@ import 'dart:collection';
 
 import 'package:appflowy_editor/appflowy_editor.dart';
 import 'package:appflowy_editor/src/render/image/image_node_widget.dart';
-import 'package:appflowy_editor/src/render/rich_text/flowy_rich_text.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:network_image_mock/network_image_mock.dart';

frontend/app_flowy/packages/appflowy_editor/test/service/internal_key_event_handlers/format_style_handler_test.dart

@@ -8,7 +8,6 @@ import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 import '../../infra/test_editor.dart';
-import 'package:appflowy_editor/src/document/built_in_attribute_keys.dart';
 
 void main() async {
   setUpAll(() {

frontend/app_flowy/packages/appflowy_editor/test/service/internal_key_event_handlers/slash_handler_test.dart

@@ -1,7 +1,6 @@
 import 'package:appflowy_editor/appflowy_editor.dart';
 import 'package:appflowy_editor/src/render/selection_menu/selection_menu_item_widget.dart';
 import 'package:appflowy_editor/src/render/selection_menu/selection_menu_service.dart';
-import 'package:appflowy_editor/src/render/selection_menu/selection_menu_widget.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 import '../../infra/test_editor.dart';

frontend/app_flowy/packages/appflowy_editor/test/service/internal_key_event_handlers/white_space_handler_test.dart

@@ -3,7 +3,6 @@ import 'package:appflowy_editor/src/service/internal_key_event_handlers/whitespa
 import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 import '../../infra/test_editor.dart';
-import 'package:appflowy_editor/src/document/built_in_attribute_keys.dart';
 
 void main() async {
   setUpAll(() {

frontend/app_flowy/packages/appflowy_editor/test/service/toolbar_service_test.dart

@@ -4,7 +4,6 @@ import 'package:appflowy_editor/src/render/toolbar/toolbar_item_widget.dart';
 import 'package:appflowy_editor/src/render/toolbar/toolbar_widget.dart';
 import 'package:flutter_test/flutter_test.dart';
 import '../infra/test_editor.dart';
-import 'package:appflowy_editor/src/document/built_in_attribute_keys.dart';
 
 void main() async {
   setUpAll(() {