Update .github/workflows/treefmt.yml

Co-authored-by: Matt Sturgeon <matt@sturgeon.me.uk>

Author: c4patino

.github/workflows/treefmt.yml

@@ -2,7 +2,7 @@ name: Formatting
 
 on:
   pull_request:
-    paths-ignore:
+    paths-ignore: &ignored
       - "**.md"
       - "**.svg"
       - ".gitignore"