pgsql: Set exit status for pgindent if pg_bsd_indent fails

Set exit status for pgindent if pg_bsd_indent fails

Also document the exit codes in the script.

The new exit code is 3, and is not overridden by the exit code set in
--check mode.

Author: Ashutosh Bapat

Discussion: https://postgr.es/m/CAExHW5sPRSiFeLdP-u1Fa5ba7YS2f0gvLjmKOobopKadJwQ_GQ@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/b20fe54c9c2194fec65db73b2778a014e7823ae0

Modified Files
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src/tools/pgindent/pgindent | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)