Обсуждение: pgsql: Fix typos and grammar in documentation and code comments

Fix typos and grammar in documentation and code comments

Comment fixes are applied on HEAD, and documentation improvements are
applied on back-branches where needed.

Author: Justin Pryzby
Discussion: https://postgr.es/m/20210408164008.GJ6592@telsasoft.com
Backpatch-through: 9.6

Branch
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REL_12_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/d42978c67afa930b1208caa9555024da10550cdb

Modified Files
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doc/src/sgml/maintenance.sgml      | 2 +-
doc/src/sgml/ref/create_table.sgml | 4 ++--
doc/src/sgml/ref/createuser.sgml   | 2 +-
3 files changed, 4 insertions(+), 4 deletions(-)