Improve SNI text

Summary:
Allow the user to see if rotation lock is enabled by reading the text.
Alternatively one has to hover it and wait for the tooltip.

Reviewers: Plasma, KWin, ngraham

Reviewed By: ngraham

Subscribers: ngraham, arvidhansson, bruns, niccolove, ndavis, zzag, kwin

Tags: KWin

Differential Revision: https://phabricator.kde.org/D19690