gpg: Adjust female-gendered salutation from Mrs. to Ms.

* g10/card-util.c (current_card_status): String changes.
(change_sex): Description change.

Since the 19th century, "Mrs." has an implication not only of female
gender, but also of marital status (married, as opposed to unmarried,
which is typically denoted as "Miss"). "Ms." is explicitly silent
about marital status.

See Wikipedia for background: https://en.wikipedia.org/wiki/Ms.

• Gnupg-Bug-Id: T4682
• Signed-off-by: Daniel Kahn Gillmor <dkg@fifthhorseman.net>