oomtop: Clarify docstring

"report them handy" is too ambigous. Clarify that the main purpose is to
list processes ordered by their memory usage.

oomtop

@@ -18,7 +18,8 @@
 #
 # See COPYING file for full licensing terms.
 # See https://www.nexedi.com/licensing for rationale and options.
-"""oomtop - extract OOM events from dmesg-like stream and report them handy"""
+"""oomtop - extract OOM events from dmesg-like stream and report them with
+   processes ordered by memory usage"""
 
 from __future__ import print_function