Fix
Fix

[ 924301 ] A leak case with cmd.py & readline & exception

by ensuring that the readline completion function is always reset
even in the case of an exception being raised.  As a bonus, this
makes the documentation for pre & postloop accurate again.

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator