bug: `BookmarkShowAll` does not work for a new, empty session

If I launch Vim and immediately call `:BookmarkShowAll`, the quickfix list is empty.

I noticed that it works as expected if I call it 3x.

Here is the resulting mapping that does what I need it to do:

```vim
nmap gm <Plug>BookmarkShowAll<Plug>BookmarkShowAll<Plug>BookmarkShowAll
```