D13370: haskell.xml: add keywords family, forall, pattern

[Li-yao Xia]

xialiyao added a reviewer: Framework: Syntax Highlighting.

REPOSITORY
  R216 Syntax Highlighting

REVISION DETAIL
  https://phabricator.kde.org/D13370

To: xialiyao, #framework_syntax_highlighting
Cc: kde-frameworks-devel, michaelh, ngraham, bruns