pgsql: Improve style guideline compliance of assorted error-reportmess

Improve style guideline compliance of assorted error-report messages.

Per the project style guide, details and hints should have leading
capitalization and end with a period.  On the other hand, errcontext should
not be capitalized and should not end with a period.  To support well
formatted error contexts in dblink, extend dblink_res_error() to take a
format+arguments rather than a hardcoded string.

Daniel Gustafsson

Discussion: https://postgr.es/m/B3C002C8-21A0-4F53-A06E-8CAB29FCF295@yesql.se

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/feb8254518752b2cb4a8964c374dd82d49ef0e0d

Modified Files
--------------
contrib/dblink/dblink.c                        | 68 ++++++++++++++++++--------
contrib/dblink/expected/dblink.out             | 24 ++++-----
contrib/file_fdw/file_fdw.c                    |  4 +-
contrib/pgcrypto/px.c                          |  4 +-
contrib/postgres_fdw/connection.c              |  2 +-
contrib/postgres_fdw/expected/postgres_fdw.out | 14 +++---
contrib/postgres_fdw/option.c                  |  2 +-
src/backend/access/transam/xlog.c              |  2 +-
src/backend/replication/logical/logical.c      |  2 +-
9 files changed, 75 insertions(+), 47 deletions(-)