Draft: dep3: clarify behaviour of Forwarded field
Cc: @guillem, @hertzog, @lucas
Add some notes explaining that it is OK to add non-URLs in the Forwarded fields in cases where the patch has been submitted but it is not possible to track its status.
Also state that the Forwared field defaults to "yes" not only when the Bug field is present, but also when the Origin of the patch is "upstream, " or "backport, ".
Prompted by the discussions in https://bugs.debian.org/851225, https://bugs.debian.org/1028503, https://bugs.debian.org/1034102, and https://bugs.debian.org/1043043.
This is just a draft; feedback welcome!