pgsql: Fix obsolete references to old-style contrib installation method

Fix obsolete references to old-style contrib installation methods.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/f1fb4b0e63a677cdc86de667c75142b88a4edb65

Modified Files
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doc/src/sgml/contrib-spi.sgml | 15 +++++++----
doc/src/sgml/contrib.sgml | 47 ++++++++++++++++++++---------------
doc/src/sgml/dict-int.sgml | 4 +-
doc/src/sgml/dict-xsyn.sgml | 4 +-
doc/src/sgml/earthdistance.sgml | 2 +-
doc/src/sgml/hstore.sgml | 6 ----
doc/src/sgml/pgstatstatements.sgml | 2 +-
doc/src/sgml/tablefunc.sgml | 4 ++-
doc/src/sgml/test-parser.sgml | 4 +-
doc/src/sgml/tsearch2.sgml | 2 +-
doc/src/sgml/unaccent.sgml | 2 +-
11 files changed, 50 insertions(+), 42 deletions(-)