pgsql: doc: Refresh more URLs in the docs

doc: Refresh more URLs in the docs

This updates some URLs that are redirections, mostly to an equivalent
using https. One URL referring to generalized partial indexes was
outdated.

Author: Kyotaro Horiguchi
Discussion: /messages/by-id/20200717.121308.1369606287593685396.horikyota.ntt@gmail.com
Backpatch-through: 9.5

Branch
------
REL9_6_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/5cd4954bb6edc5e50ade3f38ebbbf869c6313534

Modified Files
--------------
doc/src/sgml/acronyms.sgml | 4 ++--
doc/src/sgml/biblio.sgml | 23 ++++++++++-------------
doc/src/sgml/config.sgml | 2 +-
doc/src/sgml/cube.sgml | 2 +-
doc/src/sgml/dfunc.sgml | 2 +-
doc/src/sgml/earthdistance.sgml | 2 +-
doc/src/sgml/external-projects.sgml | 10 +++++-----
doc/src/sgml/geqo.sgml | 2 +-
doc/src/sgml/install-windows.sgml | 6 +++---
doc/src/sgml/intro.sgml | 2 +-
doc/src/sgml/isn.sgml | 8 ++++----
doc/src/sgml/monitoring.sgml | 2 +-
doc/src/sgml/nls.sgml | 2 +-
doc/src/sgml/pgcrypto.sgml | 6 +++---
doc/src/sgml/plperl.sgml | 2 +-
doc/src/sgml/pltcl.sgml | 2 +-
doc/src/sgml/seg.sgml | 2 +-
doc/src/sgml/textsearch.sgml | 2 +-
18 files changed, 39 insertions(+), 42 deletions(-)