message: Fixed typo in the word 'Subscription'
  Subscriptoin -> Subscription operator
diff: @@ -127,7 +127,7 @@ There are a few things to know and (try to) understand while developing operator
  - Subscribers all have `add` and `remove` methods that are used for adding and removing inner subscriptions to
  the shared underlying subscription.
  - When you `subscribe` to an Observable, the functions or Observer you passed are used to create the final `destination`
  - `Subscriber` for the chain. It's this `Subscriber` that is really also the shared `Subscriptoin` for the operator chain.
  + `Subscriber` for the chain. It's this `Subscriber` that is really also the shared `Subscription` for the operator chain.
  ### Submitting a PR for an Operator
  