feat: support customizing the block icon

[LucasXu0]

Support customizing the built-in block's icon

Here's the sample code

final iconMap = {
  BulletedListBlockKeys.type: Icons.format_list_bulleted,
  NumberedListBlockKeys.type: Icons.format_list_numbered,
  QuoteBlockKeys.type: Icons.format_quote,
  TodoListBlockKeys.type: Icons.check_box_outline_blank,
};

class CustomBlockIcon extends StatelessWidget {
  const CustomBlockIcon({super.key});

  @override
  Widget build(BuildContext context) {
    final delta = Delta()..insert('Hello World');
    final document = Document.blank()
      ..insert(
        [0],
        [
          bulletedListNode(delta: delta),
          numberedListNode(delta: delta),
          todoListNode(delta: delta, checked: false),
          quoteNode(delta: delta),
        ],
      );

    final customBlockComponentBuilders = {
      ...standardBlockComponentBuilderMap,
      BulletedListBlockKeys.type: BulletedListBlockComponentBuilder(
        iconBuilder: (_, __) => Icon(iconMap[BulletedListBlockKeys.type]),
      ),
      NumberedListBlockKeys.type: NumberedListBlockComponentBuilder(
        iconBuilder: (_, __) => Icon(iconMap[NumberedListBlockKeys.type]),
      ),
      TodoListBlockKeys.type: TodoListBlockComponentBuilder(
        iconBuilder: (_, __) => Icon(iconMap[TodoListBlockKeys.type]),
      ),
      QuoteBlockKeys.type: QuoteBlockComponentBuilder(
        iconBuilder: (_, __) => Icon(iconMap[QuoteBlockKeys.type]),
      ),
    };

    final editorState = EditorState(document: document);
    return MaterialApp(
      home: Scaffold(
        body: SafeArea(
          child: SizedBox(
            width: 500,
            child: AppFlowyEditor.custom(
              editorState: editorState,
              blockComponentBuilders: customBlockComponentBuilders,
              commandShortcutEvents: standardCommandShortcutEvents,
              characterShortcutEvents: standardCharacterShortcutEvents,
            ),
          ),
        ),
      ),
    );
  }
}

[codecov]

Codecov Report

Merging #274 (04e9f40) into main (572a174) will increase coverage by 0.04%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #274      +/-   ##
==========================================
+ Coverage   62.56%   62.60%   +0.04%     
==========================================
  Files         245      245              
  Lines       10842    10855      +13     
==========================================
+ Hits         6783     6796      +13     
  Misses       4059     4059              

Impacted Files	Coverage Δ
...block_component/bulleted_list_block_component.dart	92.42% <100.00%> (+0.36%)	⬆️
...block_component/numbered_list_block_component.dart	92.85% <100.00%> (+0.79%)	⬆️
...t/quote_block_component/quote_block_component.dart	90.38% <100.00%> (+0.58%)	⬆️
...ist_block_component/todo_list_block_component.dart	86.48% <100.00%> (ø)
...editor/toolbar/desktop/items/icon_item_widget.dart	100.00% <100.00%> (ø)