text/template: cannot find pointer method on addressable nil pointer

If you read a *T out of a []*T and it is nil, the template package cannot invoke pointer methods using it, because the template package takes its address, producing a **T with no methods. (For a non-nil *T, it's been indirected to T, so taking the address restores the *T. But if you have a nil *T, it can't be indirected, so the extra address-of hurts.)

Fix pending.