Earlier completion suggested only options for the command, this changes
options to be proposed when first character of an argument is dash.
Signed-off-by: Sami Kerola <kerolasa@iki.fi>
Users who know the short options can just hit the short option instead
of tab, and it's not likely that it would be helpful to present a list
of single character options to users who don't know them, doing so
just unnecessarily trashes the list of suggestions.
Signed-off-by: Ville Skyttä <ville.skytta@iki.fi>