Fixes example snippet in OutputStream.swift (swiftlang#33844)

Author: valeriyvan

stdlib/public/core/OutputStream.swift

@@ -225,23 +225,20 @@ public protocol LosslessStringConvertible: CustomStringConvertible {
 ///
 ///     let p = Point(x: 21, y: 30)
 ///     print(String(reflecting: p))
-///     // Prints "p: Point = {
-///     //           x = 21
-///     //           y = 30
-///     //         }"
+///     // Prints "Point(x: 21, y: 30)"
 ///
 /// After adding `CustomDebugStringConvertible` conformance by implementing the
 /// `debugDescription` property, `Point` provides its own custom debugging
 /// representation.
 ///
 ///     extension Point: CustomDebugStringConvertible {
 ///         var debugDescription: String {
-///             return "Point(x: \(x), y: \(y))"
+///             return "(\(x), \(y))"
 ///         }
 ///     }
 ///
 ///     print(String(reflecting: p))
-///     // Prints "Point(x: 21, y: 30)"
+///     // Prints "(21, 30)"
 public protocol CustomDebugStringConvertible {
   /// A textual representation of this instance, suitable for debugging.
   ///