docs: formatdomain: fix superscripts
docs: formatdomain: fix superscripts

There needs to be a space before the :sup: directive.

Signed-off-by: Ján Tomko <4cab11cfb98d3c937327354a78eb07dbb6ee2bc6@redhat.com>

crobinso/libvirt,crobinso/libvirt,jfehlig/libvirt,jfehlig/libvirt,zippy2/libvirt,zippy2/libvirt,libvirt/libvirt,nertpinx/libvirt,nertpinx/libvirt,libvirt/libvirt,olafhering/libvirt,nertpinx/libvirt,zippy2/libvirt,olafhering/libvirt,jardasgit/libvirt,libvirt/libvirt,jardasgit/libvirt,crobinso/libvirt,olafhering/libvirt,libvirt/libvirt,jardasgit/libvirt,jfehlig/libvirt,jfehlig/libvirt,nertpinx/libvirt,zippy2/libvirt,jardasgit/libvirt,nertpinx/libvirt,olafhering/libvirt,jardasgit/libvirt,crobinso/libvirt