Fix typo (actions#503)

Freed-Wu · web-flow · commit 13a464fa1180 · 2022-09-21T00:45:00.000+02:00
diff --git a/docs/advanced-usage.md b/docs/advanced-usage.md
@@ -322,7 +322,7 @@ jobs:
 
 **cache-hit** output is available with a boolean value that indicates whether a cache hit occurred on the primary key:
 
-```
+```yaml
 jobs:
   build:
     runs-on: ubuntu-latest
