The bash prompt would display a commit's object name when having checked
out a lightweight tag. Provide `--tags` to `git describe` in the completion
script, so it will display lightweight tag names, as it already does for
annotated tags.
Signed-off-by: Daniel Knittl-Frank <knittl89+git@googlemail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>