minor changes in catalog file recover

Author: Omesh2004

internal/exercises/catalog.yaml

@@ -202,7 +202,7 @@ projects:
     - "Use `t.Unix()` to convert time back to epoch."
     - "Remember Go’s `time.Parse` can help parse date strings."
 
-- slug: recover
+- slug: 110_recover
   title: Safe Panic Recovery
   difficulty: medium
   topics: ["panic", "recover", "defer"]