Make it possible to show all spaces in the document
Summary:
It's a feature offered by several editors. Now we allow to render none, only trailing and all of them.
BUG: 381267
BUG: 342811
Test Plan: Tested locally
Reviewers: Kate, cullmann
Reviewed By: Kate, cullmann
Subscribers: cullmann, ngraham, kwrite-devel, kde-frameworks-devel
Tags: Kate, Frameworks
Differential Revision: https://phabricator.kde.org/D19163