pgsql: doc: clarify text around MVCC example query

doc: clarify text around MVCC example query

Reported-by: marlene.brandstaetter@cargonet.software

Discussion: /messages/by-id/167765529052.987840.12345375075704447735@wrigleys.postgresql.org

Backpatch-through: master

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/2fa255ce9b9536450c9f86bd7c15778f58cf3777

Modified Files
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doc/src/sgml/mvcc.sgml | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)