chore: Add Offcanvas extension to shortcodes and filters

Author: mcanouil

docs/extensions/listings/shortcodes-and-filters.yml

@@ -492,6 +492,12 @@
   description: >
     Embed [Nutshell](https://ncase.me/nutshell/) expandable explanations in HTML documents.
 
+- name: Offcanvas
+  path: https://github.com/mcanouil/quarto-offcanvas
+  author: '[Mickaël CANOUIL](https://github.com/mcanouil)'
+  description: >
+    Quarto extension to create Bootstrap offcanvas components in HTML documents.
+
 - name: open-social-comments
   path: https://github.com/AndreasThinks/quarto-open-social-comments
   author: '[AndreasThinks](https://github.com/AndreasThinks/)'