pgsql: doc: "Latest checkpoint location" will not match in pg_upgrade

doc:  "Latest checkpoint location" will not match in pg_upgrade

Mention that "Latest checkpoint location" will not match in pg_upgrade
if the standby server is still running during the upgrade, which is
possible.  "Match" text first appeared in PG 9.5.

Reported-by: Paul Bonaud

Discussion: https://postgr.es/m/c7268794-edb4-1772-3bfd-04c54585c24e@trainline.com

Backpatch-through: 9.5

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/cc2e457fe8a3f685b4f9b9dce05b0c027b39459f

Modified Files
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doc/src/sgml/ref/pgupgrade.sgml | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)