pgsql: doc: clarify behavior of pg_upgrade's clone mode

doc: clarify behavior of pg_upgrade's clone mode

Be more precise about the benefits of using clone mode.

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/26950273dc27ec7775029cffe1140165f942325d

Modified Files
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doc/src/sgml/ref/pgupgrade.sgml | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)