pgsql: doc: clarify that SSPI and GSSAPI are interchangeable

doc: clarify that SSPI and GSSAPI are interchangeable

Reported-by: tpo_deb@sourcepole.ch

Discussion: /messages/by-id/167846222574.1803490.15815104179136215862@wrigleys.postgresql.org

Backpatch-through: 11

Branch
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REL_16_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/608ccdbe250a39e21727a05d9f6f6ba0e20476d9

Modified Files
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doc/src/sgml/client-auth.sgml | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)