blame: print unblamable and ignored commits in porcelain mode

blame: print unblamable and ignored commits in porcelain mode

The 'git-blame(1)' command allows users to ignore specific revisions via
the '--ignore-rev <rev>' and '--ignore-revs-file <file>' flags. These
flags are often combined with the 'blame.markIgnoredLines' and
'blame.markUnblamableLines' config options. These config options prefix
ignored and unblamable lines with a '?' and '*', respectively.

However, this option was never extended to the porcelain mode of
'git-blame(1)'. Since the documentation does not indicate this
exclusion, it is a bug.

Fix this by printing 'ignored' and 'unblamable' respectively for the
options when using the porcelain modes.

Helped-by: Patrick Steinhardt <ps@pks.im>
Helped-by: Toon Claes <toon@iotcl.com>
Helped-by: Phillip Wood <phillip.wood123@gmail.com>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>