channel: update documentation for cancellation

Author: twittemb

Sources/AsyncAlgorithms/AsyncAlgorithms.docc/Guides/Channel.md

@@ -51,7 +51,7 @@ public final class AsyncThrowingChannel<Element: Sendable, Failure: Error>: Asyn
 }
 ```
 
-Channels are intended to be used as communication types between tasks. Particularly when one task produces values and another task consumes said values. On the one hand, the back pressure applied by `send(_:)` via the suspension/resume ensures that the production of values does not exceed the consumption of values from iteration. This method suspends after enqueuing the event and is resumed when the next call to `next()` on the `Iterator` is made. On the other hand, the call to `finish()` or `fail(_:)` immediately resumes all the pending operations for every producers and consumers. Thus, every suspended `send(_:)` operations instantly resume, so as every suspended `next()` operations by producing a nil value, or by throwing an error, indicating the termination of the iterations. Further calls to `send(_:)` will immediately resume.
+Channels are intended to be used as communication types between tasks. Particularly when one task produces values and another task consumes said values. On the one hand, the back pressure applied by `send(_:)` via the suspension/resume ensures that the production of values does not exceed the consumption of values from iteration. This method suspends after enqueuing the event and is resumed when the next call to `next()` on the `Iterator` is made. On the other hand, the call to `finish()` or `fail(_:)` immediately resumes all the pending operations for every producers and consumers. Thus, every suspended `send(_:)` operations instantly resume, so as every suspended `next()` operations by producing a nil value, or by throwing an error, indicating the termination of the iterations. Further calls to `send(_:)` will immediately resume. The calls to `send(:)` and `next()` will immediately resume when their supporting task is cancelled, other operations from other tasks will remain active.
 
 ```swift
 let channel = AsyncChannel<String>()

Sources/AsyncAlgorithms/AsyncChannel.swift

@@ -235,6 +235,7 @@ public final class AsyncChannel<Element: Sendable>: AsyncSequence, Sendable {
   /// Send an element to an awaiting iteration. This function will resume when the next call to `next()` is made
   /// or when a call to `finish()` is made from another Task.
   /// If the channel is already finished then this returns immediately
+  /// If the task is cancelled, this function will resume. Other sending operations from other tasks will remain active.
   public func send(_ element: Element) async {
     let generation = establish()
     let sendTokenStatus = ManagedCriticalState<ChannelTokenStatus>(.new)

Sources/AsyncAlgorithms/AsyncThrowingChannel.swift

@@ -297,6 +297,7 @@ public final class AsyncThrowingChannel<Element: Sendable, Failure: Error>: Asyn
   /// Send an element to an awaiting iteration. This function will resume when the next call to `next()` is made
   /// or when a call to `finish()`/`fail(_:)` is made from another Task.
   /// If the channel is already finished then this returns immediately
+  /// If the task is cancelled, this function will resume. Other sending operations from other tasks will remain active.
   public func send(_ element: Element) async {
     let generation = establish()
     let sendTokenStatus = ManagedCriticalState<ChannelTokenStatus>(.new)