Typo in docs/reference/async.md

[aboyett]

The Parallelism section of the Async documentation currently contains "Should you wish to restrict concurrenty for certain functions". Concurrenty is not a word.

Proposed change

The word concurrenty should be changed to concurrency.

-> Alternatively you can increase the parallelism by setting the queue worker's "max_inflight" option to a value greater than one. This will cause the queue-worker to concurrently receive up to max_inflight many messages and simultaneously invoke their corresponding functions. Should you wish to restrict concurrenty for certain functions, please make use of  [multiple queues](#Multiple-queues) and separate these functions accordingly. When scaling up a queue worker, please be aware that you will get up to 'n * max_inflight' parallel function invocations.
+> Alternatively you can increase the parallelism by setting the queue worker's "max_inflight" option to a value greater than one. This will cause the queue-worker to concurrently receive up to max_inflight many messages and simultaneously invoke their corresponding functions. Should you wish to restrict concurrency for certain functions, please make use of  [multiple queues](#Multiple-queues) and separate these functions accordingly. When scaling up a queue worker, please be aware that you will get up to 'n * max_inflight' parallel function invocations.

Context

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• Please also follow the troubleshooting guide and paste in any other diagnostic information you have:

[alexellis]

Thanks for spotting that. @viveksyngh could you take this please?