docs: formatdomain: Tweak disk discard= docs
docs: formatdomain: Tweak disk discard= docs

Change from

  'controls whether to discard ... requests are ignored'

to

  'controls whether discard requests ... are ignored'

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