docs: add unique id extension

docs/src/docPages/api/extensions.md

@@ -25,6 +25,7 @@ There are also some extensions with more capabilities. We call them [nodes](/api
 | [History](/api/extensions/history)                          | Included                                         | [GitHub](https://github.com/ueberdosis/tiptap/blob/main/packages/extension-history/)              |
 | [Placeholder](/api/extensions/placeholder)                  | –                                                | [GitHub](https://github.com/ueberdosis/tiptap/blob/main/packages/extension-placeholder/)          |
 | [TextAlign](/api/extensions/text-align)                     | –                                                | [GitHub](https://github.com/ueberdosis/tiptap/blob/main/packages/extension-text-align/)           |
+| [UniqueId](/api/extensions/unique-id)                       | –                                                | Requires a tiptap pro subscription                                                                |
 | [Typography](/api/extensions/typography)                    | –                                                | [GitHub](https://github.com/ueberdosis/tiptap/blob/main/packages/extension-typography/)           |
 
 You don’t have to use it, but we prepared a `@tiptap/starter-kit` which includes the most common extensions. Read more about [`StarterKit`](/guide/configuration#default-extensions).

docs/src/docPages/api/extensions/unique-id.md

@@ -0,0 +1,10 @@
+# UniqueId
+:::pro Pro extension
+The UniqueId extension will be the first tiptap pro extension we’ll release on top of all the free extensions. Access to the extension and the documentation will require a tiptap pro subscription.
+:::
+
+The `UniqueId` extension adds unique IDs to all nodes. The extension keeps track of your nodes, even if you split them, merge them, undo/redo changes, crop content, paste content … It just works.
+
+Also, you can configure which node types get an unique ID, and which not, and you can customize how those IDs are generated.
+
+We’re preparing everything to release that extension, give us a few more days. If you can’t wait to purchase a tiptap pro license and get access to the extensions, send us an email to [humans@tiptap.dev](mailto:humans@tiptap.dev).

docs/src/docPages/links.yaml

@@ -359,6 +359,9 @@
           link: /api/extensions/text-align
         - title: Typography
           link: /api/extensions/typography
+        - title: UniqueId
+          link: /api/extensions/unique-id
+          type: pro
     - title: Utilities
       link: /api/utilities
       redirect: /api/utilities/html