news: Document predictable file names for memory-backend-file
news: Document predictable file names for memory-backend-file

Signed-off-by: Michal Privoznik <83d82aaba2eed257f4814b0c239c260c4caaadf0@redhat.com>
Reviewed-by: John Ferlan <87558058f6f829e5ec976c8ef960720af4ff9c7d@redhat.com>

nertpinx/libvirt,libvirt/libvirt,crobinso/libvirt,fabianfreyer/libvirt,eskultety/libvirt,eskultety/libvirt,crobinso/libvirt,fabianfreyer/libvirt,zippy2/libvirt,olafhering/libvirt,zippy2/libvirt,libvirt/libvirt,andreabolognani/libvirt,eskultety/libvirt,crobinso/libvirt,jardasgit/libvirt,libvirt/libvirt,fabianfreyer/libvirt,zippy2/libvirt,nertpinx/libvirt,andreabolognani/libvirt,jardasgit/libvirt,jardasgit/libvirt,olafhering/libvirt,fabianfreyer/libvirt,olafhering/libvirt,olafhering/libvirt,crobinso/libvirt,nertpinx/libvirt,andreabolognani/libvirt,andreabolognani/libvirt,jfehlig/libvirt,libvirt/libvirt,fabianfreyer/libvirt,jfehlig/libvirt,eskultety/libvirt,jardasgit/libvirt,jardasgit/libvirt,zippy2/libvirt,nertpinx/libvirt,nertpinx/libvirt,andreabolognani/libvirt,jfehlig/libvirt,eskultety/libvirt,jfehlig/libvirt