Fix indentation - move prose out of code listing

Fixes: rdar://145075268

Author: amartini51

stdlib/public/core/UnsafeBufferPointer.swift.gyb

@@ -387,9 +387,9 @@ extension Unsafe${Mutable}BufferPointer where Element: ~Copyable {
   ///     print(numbers)
   ///     // Prints "[2, 1, 4, 3, 5]"
   ///
-  ///     Uninitialized memory cannot be initialized to a nontrivial type
-  ///     using this subscript. Instead, use an initializing method, such as
-  ///     `initializeElement(at:to:)`
+  /// Uninitialized memory cannot be initialized to a nontrivial type
+  /// using this subscript. Instead, use an initializing method, such as
+  /// `initializeElement(at:to:)`
 %else:
   /// The following example uses the buffer pointer's subscript to access every
   /// other element of the buffer: