Add tooltips to krunner configure and close buttons
Summary:
Shows tooltips for buttons left and right of the search box.
FEATURE: 398943
Test Plan: Manually test appearance of tooltips, unlikely to cause new issues.
Reviewers: VDG, acrouthamel, ngraham
Reviewed By: VDG, acrouthamel, ngraham
Subscribers: ngraham, plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D15749