[COMMITTERS] pgsql: Doc: update versioning information in libpq.sgml.

Doc: update versioning information in libpq.sgml.

The descriptions of PQserverVersion and PQlibVersion hadn't been updated
for the new two-part version-numbering approach.  Fix that.

In passing, remove some trailing whitespace elsewhere in the file.

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/e22efaabf16e3972b91893d89597407d142fb309

Modified Files
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doc/src/sgml/libpq.sgml | 91 ++++++++++++++++++++++++++++++++++---------------
1 file changed, 63 insertions(+), 28 deletions(-)