doc: Update pg_upgrade documentation to match recent description changes.
Commit 792353f7d52 updated the pg_dump and pg_dumpall documentation to
clarify which statistics are not included in their output. The pg_upgrade
documentation contained a nearly identical description, but it was not updated
doc: Update pg_upgrade documentation to match recent description changes.
Commit 792353f7d52 updated the pg_dump and pg_dumpall documentation to
clarify which statistics are not included in their output. The pg_upgrade
documentation contained a nearly identical description, but it was not updated
