message: docs(subscription): mention 100 stream limit
diff: @@ -134,6 +134,12 @@ export type SetSubscriptionMetadataResponse = MetadataResponse;
  * nack of such message when the processing is done. **Note:** message
  * redelivery is still possible.
  *
  + * By default each {@link PubSub} instance can handle 100 open streams, with
  + * default options this translates to less than 20 Subscriptions per PubSub
  + * instance. If you wish to create more Subscriptions than that, you can either
  + * create multiple PubSub instances or lower the
  + * `options.streamingOptions.maxStreams` value on each Subscription object.
  + *
  * @class
  *
  * @param {PubSub} pubsub PubSub object.
  