This reverts commit 4bf11067b3955ed6488616783d0b685d3ae41f89.

Doesn't help, and wastes time.

This reverts commit 3d66d85f971d94758fdff080149da00b3efd976f.

Looks like we need not use that anymore

For screen reader's sake, make the shortcut empty when hidden,
otherwise a more or less random value is presented.  The actual value
is whatever the render was last used with, remembering cell renderers
are reused for every row.

This could also be fixed in the accessibility implementation side, but
we rely on GTK's, so it's easier to clean it up here than modify GTK or
subclass it further.