docs: migrate to @nuxthq/ui-kit (#405)

Co-authored-by: Sébastien Chopin <seb@nuxt.com>

docs/content/3.forms/5.checkbox.md

@@ -1,6 +1,9 @@
 ---
-github: true
 description: Display a checkbox field.
+links:
+  - label: GitHub
+    icon: i-simple-icons-github
+    to: https://github.com/nuxtlabs/ui/blob/dev/src/runtime/components/forms/Checkbox.vue
 ---
 
 ## Usage