pgsql: Fix some typos, grammar and style in docs and comments

Fix some typos, grammar and style in docs and comments

The portions fixing the documentation are backpatched where needed.

Author: Justin Pryzby
Discussion: https://postgr.es/m/20210210235557.GQ20012@telsasoft.com
backpatch-through: 9.6

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/bcf2667bf62d72faced64cb60ffbd2e599a0ebe8

Modified Files
--------------
contrib/pageinspect/heapfuncs.c | 2 +-
doc/src/sgml/charset.sgml | 2 +-
doc/src/sgml/extend.sgml | 2 +-
doc/src/sgml/fdwhandler.sgml | 9 +++----
doc/src/sgml/logicaldecoding.sgml | 43 +++++++++++++++---------------
doc/src/sgml/pageinspect.sgml | 2 +-
doc/src/sgml/postgres-fdw.sgml | 20 +++++++-------
doc/src/sgml/protocol.sgml | 4 +--
doc/src/sgml/ref/alter_subscription.sgml | 2 +-
doc/src/sgml/ref/create_type.sgml | 2 +-
doc/src/sgml/ref/drop_index.sgml | 2 +-
doc/src/sgml/rules.sgml | 2 +-
doc/src/sgml/wal.sgml | 18 ++++++-------
src/backend/access/common/heaptuple.c | 4 +--
src/backend/access/transam/xlogutils.c | 3 +--
src/backend/commands/amcmds.c | 2 +-
src/backend/executor/nodeAgg.c | 3 +--
src/backend/optimizer/prep/prepagg.c | 2 +-
src/backend/storage/ipc/procarray.c | 2 +-
src/backend/utils/adt/jsonpath_exec.c | 2 +-
src/backend/utils/adt/selfuncs.c | 2 +-
src/backend/utils/cache/catcache.c | 2 +-
src/bin/pg_rewind/libpq_source.c | 2 +-
src/bin/pgbench/pgbench.c | 2 +-
src/include/pg_config_manual.h | 2 +-
src/interfaces/ecpg/include/sqlda-native.h | 2 +-
src/test/regress/expected/geometry.out | 2 +-
src/test/regress/expected/tuplesort.out | 2 +-
src/test/regress/sql/geometry.sql | 2 +-
src/test/regress/sql/tuplesort.sql | 2 +-
30 files changed, 73 insertions(+), 75 deletions(-)