plugins/buttonrebinds: Support rebinding to modifier keys
Allow rebinding buttons to send modifier keys (Control, Alt, Meta, Shift) without any other key. This is necessary for restoring the functionality kcm-wacomtablet had under X11 for wayland.
An alternative might be to add the modifier keys to KKeyServer so they'll be found by KKeyServer::keyQtToSymX, however I'm afraid that touching that table could break random things.
I will edit this MR with the corresponding MR to kcm_tablet. edit: kcm MR
Edited by Tino Lorenz