Missing final semi-colon in .desktop's Categories.

"Those keys which have several values should have a semicolon as the trailing
character."
  -- http://standards.freedesktop.org/desktop-entry-spec/1.0/ar01s03.html

Signed-off-by: James Rowe <jnrowe@gmail.com>
Reviewed-by: Jeffrey C. Ollie <jeff@ocjtech.us>