pgsql: Fix variety of typos and grammar mistakes

Fix variety of typos and grammar mistakes

This commit includes a batch of fixes for various minor typos and
grammar mistakes, that have been proposed to the hackers mailing list
since the beginning of January.

Similar batches are planned on a bi-monthly basis depending on the
amount received, with the next one for the end of April.

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/462fe0ff6215ae222fc866af621e4b86462289b1

Modified Files
--------------
contrib/amcheck/verify_nbtree.c | 2 +-
src/backend/access/brin/brin_minmax_multi.c | 2 +-
src/backend/access/gist/gistget.c | 4 ++--
src/backend/access/transam/multixact.c | 2 +-
src/backend/access/transam/xlogrecovery.c | 6 +++---
src/backend/backup/basebackup_copy.c | 2 +-
src/backend/commands/extension.c | 2 +-
src/backend/statistics/extended_stats_funcs.c | 2 +-
src/backend/storage/smgr/smgr.c | 2 +-
src/bin/pg_basebackup/pg_receivewal.c | 2 +-
src/bin/pg_resetwal/pg_resetwal.c | 2 +-
src/fe_utils/astreamer_zstd.c | 2 +-
src/include/nodes/parsenodes.h | 2 +-
13 files changed, 16 insertions(+), 16 deletions(-)