Update custom-formats.yml (#1289)

Author: georgestagg

docs/extensions/listings/custom-formats.yml

@@ -75,3 +75,9 @@
   author: "[Kazuharu Yanagimoto](https://github.com/kazuyanagimoto)"
   description: |
     Quarto Typst template for the Awesome CV
+
+- name: quarto-live
+  path: https://github.com/r-wasm/quarto-live
+  author: "[George Stagg](https://github.com/georgestagg)"
+  description: |
+    WebAssembly powered "live" formats for Quarto HTML documents and Revealjs slides, adding interactive code blocks and exercises for R and Python.