pgsql: doc: Fix man page whitespace issues

doc: Fix man page whitespace issues

Whitespace between tags is significant, and in some cases it creates
extra vertical space in man pages. The fix is to remove some newlines
in the markup.

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/d7ab2a9a3c0a2800ab36bb48d1cc97370067777e

Modified Files
--------------
doc/src/sgml/ref/alter_publication.sgml | 3 +--
doc/src/sgml/ref/alter_subscription.sgml | 3 +--
doc/src/sgml/ref/alter_table.sgml | 3 +--
doc/src/sgml/ref/create_subscription.sgml | 3 +--
doc/src/sgml/ref/create_trigger.sgml | 8 +++-----
doc/src/sgml/ref/drop_procedure.sgml | 3 +--
doc/src/sgml/ref/merge.sgml | 6 ++----
doc/src/sgml/ref/pg_basebackup.sgml | 3 +--
doc/src/sgml/ref/pgbench.sgml | 12 ++++--------
9 files changed, 15 insertions(+), 29 deletions(-)