docs: correct improper information about domain states in virsh manpage
docs: correct improper information about domain states in virsh manpage

Commit 24d4a0a1f removed the non-existent "dying" state from the list
of possible domain states given in the virsh manpage, but didn't
correct the count of states from 8 down to 7. This patch fixes that
mismatch by completely removing any reference to the exact number of
states (thus preventing a potential future mismatch), while wording
the sentence in a more readable/truthful manner.

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