D9616: update info about kateconfig file and extended options

[Burkhard Lück]

lueck added a reviewer: Documentation.

REPOSITORY
  R40 Kate

REVISION DETAIL
  https://phabricator.kde.org/D9616

To: lueck, #kate, dhaumann, #documentation
Cc: michaelh, kevinapavew, ngraham, demsking, cullmann, sars, dhaumann