pgsql: doc: Clarify when SSL actually means TLS

doc: Clarify when SSL actually means TLS

SSL has become the de facto term to mean an end-to-end encrypted channel
regardless of protocol used, even though the SSL protocol is deprecated.
Clarify what we mean with SSL in our documentation, especially for new
users who might be looking for TLS.

Reviewed-by: Robert Haas <robertmhaas(at)gmail(dot)com>
Discussion: https://postgr.es/m/D4ABB281-6CFD-46C6-A4E0-8EC23A2977BC@yesql.se

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/860ea46ba7be69c46c37a96983e1ddca9d630c2e

Modified Files
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doc/src/sgml/config.sgml | 8 +++++++-
doc/src/sgml/libpq.sgml | 6 ++++--
doc/src/sgml/runtime.sgml | 15 ++++++++++++++-
3 files changed, 25 insertions(+), 4 deletions(-)