KCM/GlobalShortut: convert FOREACH and old signal syntax
Test Plan: Builds, changed a shortcut and back again
Reviewers: ervin, bport, crossi, hchain, Plasma
Reviewed By: ervin
Subscribers: ahmadsamir, davidedmundson, plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D28282