Update usage of backpressure in readme

Author: huntharo

README.md

@@ -2,7 +2,7 @@
 
 # Overview
 
-`@shutterstock/p-map-iterable` provides several classes that allow processing results of `p-map`-style mapper functions by iterating the results as they are completed, with back pressure to limit the number of items that are processed ahead of the consumer.
+`@shutterstock/p-map-iterable` provides several classes that allow processing results of `p-map`-style mapper functions by iterating the results as they are completed, with backpressure to limit the number of items that are processed ahead of the consumer.
 
 A common use case for `@shutterstock/p-map-iterable` is as a "prefetcher" that will fetch, for example, AWS S3 files in an AWS Lambda function. By prefetching large files the consumer is able to use 100% of the paid-for Lambda CPU time for the JS thread, rather than waiting idle while the next file is fetched. The backpressure (set by `maxUnread`) prevents the prefetcher from consuming unlimited memory or disk space by racing ahead of the consumer.
 
@@ -117,7 +117,7 @@ These diagrams illustrate the differences in operation betweeen `p-map`, `p-queu
   - User supplied sync or async mapper function
   - Exposes an async iterable interface for consuming mapped items
   - Allows a maximum queue depth of mapped items - if the consumer stops consuming, the queue will fill up, at which point the mapper will stop being invoked until an item is consumed from the queue
-  - This allows mapping with back pressure so that the mapper does not consume unlimited resources (e.g. memory, disk, network, event loop time) by racing ahead of the consumer
+  - This allows mapping with backpressure so that the mapper does not consume unlimited resources (e.g. memory, disk, network, event loop time) by racing ahead of the consumer
 - [IterableQueueMapper](https://tech.shutterstock.com/p-map-iterable/classes/IterableQueueMapper.html)
   - Wraps `IterableMapper`
   - Adds items to the queue via the `enqueue` method
@@ -142,7 +142,7 @@ These diagrams illustrate the differences in operation betweeen `p-map`, `p-queu
 
 See [p-map](https://github.com/sindresorhus/p-map) docs for a good start in understanding what this does.
 
-The key difference between `IterableMapper` and `pMap` are that `IterableMapper` does not return when the entire mapping is done, rather it exposes an iterable that the caller loops through. This enables results to be processed while the mapping is still happening, while optionally allowing for back pressure to slow or stop the mapping if the caller is not consuming items fast enough. Common use cases include `prefetching` items from a remote service - the next set of requests are dispatched asyncronously while the current responses are processed and the prefetch requests will pause when the unread queue fills up.
+The key difference between `IterableMapper` and `pMap` are that `IterableMapper` does not return when the entire mapping is done, rather it exposes an iterable that the caller loops through. This enables results to be processed while the mapping is still happening, while optionally allowing for backpressure to slow or stop the mapping if the caller is not consuming items fast enough. Common use cases include `prefetching` items from a remote service - the next set of requests are dispatched asyncronously while the current responses are processed and the prefetch requests will pause when the unread queue fills up.
 
 See [examples/iterable-mapper.ts](./examples/iterable-mapper.ts) for an example.