fix test that checks validity of generated docs
fix test that checks validity of generated docs

dart-lang/dartdoc,keertip/dartdoc,astashov/dartdoc,keertip/dartdoc,dart-lang/dartdoc,dart-lang/dartdoc,astashov/dartdoc,astashov/dartdoc,dart-lang/dartdoc,keertip/dartdoc,keertip/dartdoc,astashov/dartdoc