Add draw-highlight action icons
Summary:
This patch adds draw-highlight icons requested by Okular for D15580.
I went with a style of showing the whole marker to be consistent with our other draw-* icons.
The stroke is 2px thick to illustrate the broad tip of the highlighter.
CCBUG: 408283
Test Plan:
Reviewers: VDG, ngraham, ndavis
Reviewed By: VDG, ngraham, ndavis
Subscribers: ngraham, ndavis, kde-frameworks-devel
Tags: Frameworks
Differential Revision: https://phabricator.kde.org/D24493