Reflow code snippet in doc comment.

Author: Chris Adamson

stdlib/public/Concurrency/AsyncStream.swift

@@ -243,8 +243,8 @@ public struct AsyncStream<Element> {
   /// a private `keepRunning` variable becomes `false`, the inner `while` loop
   /// exits and the stream finishes.
   ///
-  ///     let stream = AsyncStream<Int>(
-  ///         Int.self, bufferingPolicy: .bufferingNewest(5)) { continuation in
+  ///     let stream = AsyncStream<Int>(Int.self,
+  ///                                   bufferingPolicy: .bufferingNewest(5)) { continuation in
   ///             Task.detached {
   ///                 while keepRunning {
   ///                     await Task.sleep(1 * 1_000_000_000)

stdlib/public/Concurrency/AsyncThrowingStream.swift

@@ -274,8 +274,8 @@ public struct AsyncThrowingStream<Element, Failure: Error> {
   /// exits and the stream finishes. If the random number is divisble by 5 with
   /// no remainder, the stream throws a `MyRandomNumberError`.
   ///
-  ///     let stream = AsyncThrowingStream<Int, Error>(
-  ///         Int.self, bufferingPolicy: .bufferingNewest(5)) { continuation in
+  ///     let stream = AsyncThrowingStream<Int, Error>(Int.self,
+  ///                                                  bufferingPolicy: .bufferingNewest(5)) { continuation in
   ///             Task.detached {
   ///                 while (keepRunning) {
   ///                     await Task.sleep(1 * 1_000_000_000)