Minor comment fix for pg_config_manual.h

Hi

Attached is mainly to fix a comment in $subject which has a typo in the referenced initdb
option ("--walsegsize", should be "--wal-segsize"), and while I'm there also adds a
couple of "the" for readability.


Regards

Ian Barwick

-- 
  Ian Barwick                   http://www.2ndQuadrant.com/
  PostgreSQL Development, 24x7 Support, Training & Services