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

docs/src/docPages/api/extensions/dropcursor.md

@@ -0,0 +1,25 @@
+# Dropcursor
+
+## Installation
+```bash
+# with npm
+npm install @tiptap/extension-dropcursor
+
+# with Yarn
+yarn add @tiptap/extension-dropcursor
+```
+
+## Settings
+*None*
+
+## Commands
+*None*
+
+## Keyboard shortcuts
+*None*
+
+## Source code
+[packages/extension-dropcursor/](https://github.com/ueberdosis/tiptap-next/blob/main/packages/extension-dropcursor/)
+
+## Usage
+<demo name="Extensions/Dropcursor" highlight="" />