Bug#1131015: mention Files-Excluded/Included-* in copyright-format-1.0.xml

> Hi!  The copyright specification
>
> https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
>
> do not mention Files-Excluded/Included which are supported for a long
> time by uscan and other tools.
>
> What do you think about the attached patch to fix this?

Yes, I think we should document these in the spec.

One comment about your patch is that it refers to the other tools'
documentation for what the contents of the fields should be.  But Policy
should probably become the canonical source here.  So can you instead
document the format of the contents of the fields?