Add quarto-custom-callout (#1398) (#1399)

(cherry picked from commit 8b0f0f5)

Co-authored-by: James J Balamuta <[email protected]>

Author: github-actions[bot]

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

@@ -118,6 +118,13 @@
   description: >
     Handle critic markup syntax for tracking changes.
 
+- name: custom-callout
+  path: https://github.com/coatless-quarto/custom-callout
+  author: '[James Joseph Balamuta](https://github.com/coatless/)'
+  description: >
+    Create custom callouts with different colors, icons, and appearance 
+    in your document.
+
 - name: d2
   path: https://github.com/data-intuitive/quarto-d2
   author: '[Data Intuitive](https://github.com/data-intuitive/)'