pgsql: docs: Fix snapshot name in SET TRANSACTION docs.

docs: Fix snapshot name in SET TRANSACTION docs.

Commit 6c2003f8a1 changed the snapshot names mentioned in
SET TRANSACTION docs, however, there was one place that
the commit missed updating the name.

Back-patch to all supported versions.

Author: Japin Li
Reviewed-by: Fujii Masao
Discussion: https://postgr.es/m/MEYP282MB1669BD4280044501165F8B07B64F9@MEYP282MB1669.AUSP282.PROD.OUTLOOK.COM

Branch
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REL_11_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/ec6c263db90338d25cf1775efed609b3307b865b

Modified Files
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doc/src/sgml/ref/set_transaction.sgml | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)