Summary:
this is the milou part: refine keyboard navigation and
semantically mark the entries with the correct text
to be read by orca

Test Plan: tested keyboard navigation and made sure orca reads the correct meaningful text

Reviewers: #plasma, davidedmundson, broulik

Reviewed By: #plasma, davidedmundson

Subscribers: plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D7766