fix margins in OverlaySheet
From the mailing list thread:
Re: 2 kirigami fixes for a point release
> Kirigami seems to be rather unstable, I wonder if anything can be done to
> improve upon that [*].
One important thing seems to have been getting sloppy in those repos;
mandatory code reviews.
That's an easy thing to enforce, and we know it makes a huge difference to
Even if no-one comments, the extra delay of it running on your own
system delivers a lot.
I fully agree.
(CC'ing the developer lists)