Mark whatisdoing.sh as deprecated in top-comment.

Author: antirez

utils/whatisdoing.sh

@@ -1,4 +1,10 @@
 # This script is from http://poormansprofiler.org/
+#
+# NOTE: Instead of using this script, you should use the Redis
+# Software Watchdog, which provides a similar functionality but in
+# a more reliable / easy to use way.
+#
+# Check http://redis.io/topics/latency for more information.
 
 #!/bin/bash
 nsamples=1