Add a note that downstreams can send patches to fix these issues

Author: mgorny

source/discussions/downstream-packaging.rst

@@ -22,7 +22,8 @@ to provide some optional guidelines that project maintainers may choose to
 follow which help make downstream packaging *significantly* easier
 (without imposing any major maintenance hassles on the upstream project).
 Note that this is not an all-or-nothing proposal — anything that upstream
-maintainers can do is useful, even if it's only a small part.
+maintainers can do is useful, even if it's only a small part. Downstream
+maintainers are also willing to prepare patches to resolve these issues.
 
 Establishing a good relationship between software maintainers and downstream
 packagers can bring mutual benefits. Downstreams are often willing to share