During the initial development of the fsck-msgids.txt feature, it
has become apparent that it is very much error prone to make sure
the description in the documentation file are sorted and correctly
match what is in the fsck.h header file.
Add a quick-and-dirty Perl script and doc-lint target to sanity
check that the fsck-msgids.txt is consistent with the error type
list in the fsck.h header file.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
