bitbucketserver: Documentation for archived label
Created by: keegancsmith
Follow-up of https://github.com/sourcegraph/sourcegraph/pull/7284
Part of https://github.com/sourcegraph/sourcegraph/issues/5494
Created by: keegancsmith
Follow-up of https://github.com/sourcegraph/sourcegraph/pull/7284
Part of https://github.com/sourcegraph/sourcegraph/issues/5494