Suggest Reviewers REST endpoint: Add option to suggest CCs

The reviewer suggestion excludes existing reviewers. This means if it is
used to suggest CCs, it doesn't show existing reviewers and hence users
cannot easily move existing reviewers to CC. Add an option to suggest
accounts for CC that includes existing reviewers, but excludes existing
CCs.

Bug: Issue 11354
Change-Id: Ic8960452d1eb5fe1b4559a27d6d7104428b9be85
Signed-off-by: Edwin Kempin <ekempin@google.com>

java/com/google/gerrit/server/api/changes/ChangeApiImpl.java

@@ -449,6 +449,7 @@ class ChangeApiImpl implements ChangeApi {
       suggestReviewers.setQuery(r.getQuery());
       suggestReviewers.setLimit(r.getLimit());
       suggestReviewers.setExcludeGroups(r.getExcludeGroups());
+      suggestReviewers.setReviewerState(r.getReviewerState());
       return suggestReviewers.apply(change).value();
     } catch (Exception e) {
       throw asRestApiException("Cannot retrieve suggested reviewers", e);