Sleep after sending keypresses in bookmark tests
Sleep after sending keypresses in bookmark tests

Bookmark file wasn't updated fast enough after sending keypresses,
when saving a bookmark in testing. Add a short sleep before checking
that the newly added bookmark was written to the bookmark file.

fluks/mupdf-x11-bookmarks,fluks/mupdf-x11-bookmarks,fluks/mupdf-x11-bookmarks,fluks/mupdf-x11-bookmarks,fluks/mupdf-x11-bookmarks,fluks/mupdf-x11-bookmarks,fluks/mupdf-x11-bookmarks