KateSessionManager: Sort the jump list actions alphabetical

Summary:
...to avoid needed but expensive updates of the desktop file
and to bring back the (probably) prefered order

Reviewers: #kate, cullmann

Reviewed By: #kate, cullmann

Subscribers: cullmann, kwrite-devel, #kate

Tags: #kate

Differential Revision: https://phabricator.kde.org/D16646