ksh: escape control chars when displaying file name completions.

ksh: escape control chars when displaying file name completions.
If there are multiple matches when using autocomplete, the list of
matching file names was output as-is.  However, for a single match,
control characters are escaped before the file name is displayed.
This makes the behavior more consistent by escaping control chars
in the list of matches too.  Discussed with deraadt@, OK op@