Add doc tools to frontpage (#12179)

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- User's documentation (`docs`):
https://docs--12179.org.readthedocs.build/12179/

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- Developer's documentation (`dev`):
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Author: MilaZhou22

docs/user/index.rst

@@ -162,6 +162,9 @@ We have a few places for you to get started:
 :doc:`/tutorial/index`
   Follow the Read the Docs tutorial.
 
+:doc:`/intro/doctools`
+  Quick start for MkDocs and Docusaurus.
+
 :doc:`/examples`
   Start your journey with an example project to hit the ground running.