Add TextStyle demo for React

demos/src/Marks/TextStyle/React/index.jsx

@@ -0,0 +1,22 @@
+import React from 'react'
+import { useEditor, EditorContent } from '@tiptap/react'
+import Document from '@tiptap/extension-document'
+import Paragraph from '@tiptap/extension-paragraph'
+import Text from '@tiptap/extension-text'
+import TextStyle from '@tiptap/extension-text-style'
+
+export default () => {
+  const editor = useEditor({
+    extensions: [Document, Paragraph, Text, TextStyle],
+    content: `
+        <p><span>This has a &lt;span&gt; tag without a style attribute, so it’s thrown away.</span></p>
+        <p><span style="">But this one is wrapped in a &lt;span&gt; tag with an inline style attribute, so it’s kept - even if it’s empty for now.</span></p>
+      `,
+  })
+
+  if (!editor) {
+    return null
+  }
+
+  return <EditorContent editor={editor} />
+}