pgsql: Improve discussion of setting server parameters.

Improve discussion of setting server parameters.

Rewrite description of "include_if_exists" for clarity.  Add subsection
headings to make the structure of the page a little clearer.  A couple
other minor improvements too.

Josh Kupershmidt and Tom Lane

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/817ec1bc8227eb0d7f3bbb5725ea1de0ec73c1ea

Modified Files
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doc/src/sgml/config.sgml |  328 ++++++++++++++++++++++++---------------------
1 files changed, 175 insertions(+), 153 deletions(-)