Fix typos in comments

contrib/tsm_system_time/tsm_system_time.c

doc/src/sgml/logicaldecoding.sgml

doc/src/sgml/ref/pg_dumpall.sgml

src/backend/access/gin/ginpostinglist.c

src/backend/access/heap/heapam.c

src/backend/access/nbtree/README

src/backend/access/transam/xact.c

src/backend/replication/logical/snapbuild.c

src/backend/tsearch/dict_synonym.c

src/backend/utils/adt/jsonfuncs.c

src/test/regress/expected/event_trigger.out

src/test/regress/sql/event_trigger.sql