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

Hi

>> The text is silence on how multiple occurances of these lines behave.
>> The simplest is to just ban that, which could be added.
[...]

Repeated use of the same field within a stanza of a deb822-style file is 
already forbidden, so there's no further need to worry about any of 
these cases:

copyright-format/1.0 §4 says:

   The syntax of the file is the same as for other Debian control files,
   as specified in the Debian Policy Manual. See its section 5.1 for
   details.
And Policy §5.1 says:

   A stanza must not contain more than one instance of a particular field
   name.

mk-origtargz uses dpkg's Dpkg::Control to read the data which matches 
this requirement; likewise python-debian's debian.copyright module 
implements this already.


>> Another question is how to deal with paths containing odd characters
>> like SPC.

The mk-origtargz source uses these as what copyright-format/1.0 §4.2 
calls a "whitespace-separated list".

	split(/\s+/, $data->{ $self->config->excludestanza })

This matches all other places in copyright-format/1.0 where files or 
sets of files are described - i.e. the Files field (see §6.9).

Between §4.2 and §6.9, the details are already exhaustively described in 
the format, along with practical guidance on how to deal with a space 
character.

I would suggest that the current patch for the documentation of these 
fields should have a reference to the format of the field (§4.2) and 
useful additional information about that format (§6.9) added to it.


Would be great to get this extensively used field documented - 
apparently 4304 packages currently use it.

cheers
Stuart