pgsql: docs: list single-letter options first in command-line summary

docs: list single-letter options first in command-line summary

In a few places, the long-version options were listed before the
single-letter ones in the command summary of a few commands. This
didn't match other commands, and didn't match the option ordering later
in the same reference page.

Backpatch-through: 9.5

Branch
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REL9_5_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/47c4843a03cac9c35d97ddc42868b157731d2032

Modified Files
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doc/src/sgml/ref/reindexdb.sgml | 10 +++++-----
doc/src/sgml/ref/vacuumdb.sgml | 4 ++--
2 files changed, 7 insertions(+), 7 deletions(-)