Consider the last line number when padding hunks

[Wilfred]

E.g. in itertools f9ccc345d1001d0c47515dec3067206e096f7f33:

src/rciter_impl.rs --- 2/2 --- Rust
95 95 }
.. 96 
.. 97 
.. 98 impl<A, I> FusedIterator for RcIter<I>
.. 99     where I: FusedIterator<Item = A>
.. 100 {}

Alignment is broken here.