Correct the difference between throwing/nonthrowing.

Per tech review from @jckarter

Author: amartini51

stdlib/public/Concurrency/CheckedContinuation.swift

@@ -252,7 +252,8 @@ extension CheckedContinuation {
   }
 }
 
-/// Calls the given closure with a checked continuation.
+/// Suspends the current task,
+/// then calls the given closure with a checked continuation for the current task.
 ///
 /// - Parameters:
 ///   - function: A string identifying the declaration that is the notional
@@ -270,7 +271,8 @@ public func withCheckedContinuation<T>(
   }
 }
 
-/// Calls the given throwing closure with a checked continuation.
+/// Suspends the current task,
+/// then calls the given closure with a checked throwing continuation for the current task.
 ///
 /// - Parameters:
 ///   - function: A string identifying the declaration that is the notional
@@ -279,8 +281,8 @@ public func withCheckedContinuation<T>(
 ///   - body: A closure that takes an `UnsafeContinuation` parameter.
 ///     The closure must resume the continuation exactly once.
 ///
-/// If the closure throws an error,
-/// this function rethrows that error.
+/// If the closure calls `resume(throwing:)` on the continuation,
+/// this method thows that error.
 @available(SwiftStdlib 5.5, *)
 public func withCheckedThrowingContinuation<T>(
     function: String = #function,

stdlib/public/Concurrency/PartialAsyncTask.swift

@@ -235,16 +235,16 @@ internal func _resumeUnsafeThrowingContinuationWithError<T>(
 
 #endif
 
-/// Calls the given closure with an unsafe continuation
-/// and returns its result.
+/// Suspends the current task,
+/// then calls the given closure with the an unsafe continuation for the current task.
 ///
 /// - Parameter fn: A closure that takes an `UnsafeContinuation` parameter.
 /// The closure must resume the continuation exactly once.
 ///
 /// - Returns: The value passed to the continuation by the closure.
 ///
-/// The continuation won't start executing until the operation function returns.
-/// ◊TR: What does this mean?
+/// If the closure calls `resume(throwing:)` on the continuation,
+/// this method thows that error.
 @available(SwiftStdlib 5.5, *)
 @_alwaysEmitIntoClient
 public func withUnsafeContinuation<T>(
@@ -255,16 +255,13 @@ public func withUnsafeContinuation<T>(
   }
 }
 
-/// Calls the given closure with an unsafe continuation
-/// and returns its result or throws its error.
+/// Suspends the current task,
+/// then calls the given closure with the an unsafe throwing continuation for the current task.
 ///
 /// - Parameter fn: A closure that takes an `UnsafeContinuation` parameter.
 /// The closure must resume the continuation exactly once.
 ///
 /// - Returns: The value passed to the continuation by the closure.
-///
-/// The continuation won't start executing until the operation function returns.
-/// ◊TR: What does this mean?
 @available(SwiftStdlib 5.5, *)
 @_alwaysEmitIntoClient
 public func withUnsafeThrowingContinuation<T>(