chore(richtext-lexical): add DebugJsxConverterFeature

[GermanJablo]

Display the editor content below using the JSX converter
Added for debugging reasons, similar to TreeViewFeature

usage:

    {
      name: 'content',
      type: 'richText',
      editor: lexicalEditor({
        features: ({ defaultFeatures }) => [...defaultFeatures, DebugJsxConverterFeature()],
      }),
    },