DOC - Add Falcon web framework to the gallery (#2165)

As of [Falcon](https://github.com/falconry/falcon)
[4.0.0](https://falcon.readthedocs.io/en/latest/changes/4.0.0.html), the
framework has adopted PyData Sphinx Theme for docs.

Rendered examples can be found on ReadTheDocs:
* stable - https://falcon.readthedocs.io/
* latest - https://falcon.readthedocs.io/en/latest/


![image](https://github.com/user-attachments/assets/5a6b1d30-61a4-423e-9dfa-2690aa455c4b)

We have customized the look and feel somewhat (including light/dark
themes, custom icons, and own Pygments styles) but I shied away from
proposing this for **_Featured_** for now 😅

So far the experience has been mostly positive, this is a great theme:
easy to support both light and dark themes, both desktop and mobile out
of the box. 💯

If I were to find minor nitpicks/complaints, I think we saw a variation
of #1889 on the right sidebar, don't remember what triggers that and
whether we had a good example; also I'm not convinced about how the
layout is condensed in the interim version between wide desktop and
mobile: headings word wrapped into two lines is OK by me, but the way
icons and buttons get scattered on the right side is IMHO somewhat
peculiar:

![image](https://github.com/user-attachments/assets/aac6b797-ce2e-47c2-bddb-a032080b2be7)

Co-authored-by: gabalafou <[email protected]>

Author: vytas7

docs/examples/gallery.md

@@ -38,6 +38,9 @@ Thanks for your support!
 - title: Fairlearn
   link-alt: Fairlearn docs
   link: https://fairlearn.org/main/about/
+- title: Falcon web framework
+  link-alt: The Falcon web framework
+  link: https://falcon.readthedocs.io/
 - title: Feature-engine
   link-alt: Feature-engine docs
   link: https://feature-engine.readthedocs.io/