Migration help from using CustomRender and CustomRenderMatcher

[cgs]

With 3.0.0-alpha.6 breaking with Flutter 3.22, I'm attempting to update to beta.2.

I have the following code, but don't know where to start to migrate it to using TagExtension. Also the How To Use Extensions docs don't yet exist 😅 It would be nice to maybe get an alpha.7 version that works with Flutter 3.22 until the docs are improved. I suspect a lot of projects will be broken here...

CustomRenderMatcher supMatcher() =>
    (context) => context.tree.element?.localName == 'sup';

Html(
  data: snapshot.data?[widget.cmsKey],
  style: btmHctHtmlStyle(),
  customRenders: {
    supMatcher(): CustomRender.widget(
      widget: (con, buildChildren) => ReferenceBox(
          text: con.tree.element!.innerHtml,
          linked: true,
          leftMargin: 4.0),
    ),
  },
  onLinkTap: (String? url, RenderContext rc,
      Map<String, String> attributes, element) async {
    onLinkTap(context, url, rc, attributes, element);
  },
),

[cgs]

In the meantime I got my app running with Flutter 3.22 with alpha.6. #1422 (comment)