The "complete with known paths only" update to completion scripts
returns directory names without trailing slash to compensate the
addition of '/' done by bash that reads from our completion result.
tcsh completion code that reads from our internal completion result
does not add '/', so let it ask our complletion code to keep the '/'
at the end.
* mk/tcsh-complete-only-known-paths:
completion: handle path completion and colon for tcsh script