move nodes and marks to a separate folder, add missing extensions

docs/src/docPages/api/nodes/task-item.md

@@ -0,0 +1,28 @@
+# TaskItem
+
+## Installation
+::: warning Restrictions
+This extension is intended to be used with the [`TaskList`](/api/extensions/task-list) extension. It doesn’t work without at least using one of them.
+:::
+
+```bash
+# With npm
+npm install @tiptap/extension-task-list @tiptap/extension-task-item
+
+# Or: With Yarn
+yarn add @tiptap/extension-task-list @tiptap/extension-task-item
+```
+
+## Settings
+| Option | Type   | Default | Description                                  |
+| ------ | ------ | ------- | -------------------------------------------- |
+| class  | string | –       | Add a custom class to the rendered HTML tag. |
+
+## Commands
+*None*
+
+## Source code
+[packages/extension-task-item/](https://github.com/ueberdosis/tiptap-next/blob/main/packages/extension-task-item/)
+
+## Usage
+<demo name="Extensions/TaskItem" />