Fix `Function.apply` dartdoc.

sdk/lib/core/function.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of dart.core;
 
 /**
  * The base class for all function types.
  *
  * A function value, or an instance of a class with a "call" method, is a
  * subtype of a function type, and as such, a subtype of [Function].
  */
 abstract class Function {
   /**
    * Dynamically call [function] with the specified arguments.
    *
    * Acts the same as calling function with positional arguments
    * corresponding to the elements of [positionalArguments] and
    * named arguments corresponding to the elements of [namedArguments].
    *
    * This includes giving the same errors if [function] isn't callable or
    * if it expects different parameters.
    *
    * Example:
-   *       Map<Symbol, dynamic> namedArguments = new Map<Symbol, dynamic>();
-   *       namedArguments[const Symbol("f")] = 4;
-   *       namedArguments[const Symbol("g")] = 5;
-   *       Function.apply(foo, [1,2,3], namedArguments);
+   * ```
+   * var namedArguments = new Map<Symbol, dynamic>();
+   * namedArguments[const Symbol("f")] = 4;
+   * namedArguments[const Symbol("g")] = 5;
+   * Function.apply(foo, [1,2,3], namedArguments);
+   * ```

[Lasse Reichstein Nielsen, 2017/08/23 05:53:31]

How about just doing:

  Function.apply(foo, [1, 2, 3], {#f: 4, #g: 5});

and drop the imperative map creation?

[floitsch, 2017/08/23 18:09:00]

done in https://codereview.chromium.org/3002193002

    *
    * gives exactly the same result as
-   *       foo(1, 2, 3, f: 4, g: 5).
+   * ```
+   * foo(1, 2, 3, f: 4, g: 5).
+   * ```
    *
    * If [positionalArguments] is null, it's considered an empty list.
    * If [namedArguments] is omitted or null, it is considered an empty map.
    */
   external static apply(Function function, List positionalArguments,
       [Map<Symbol, dynamic> namedArguments]);
 
   /**
    * Returns a hash code value that is compatible with `operator==`.
    */
@@ skipping 15 matching lines @@
    *
    * Function expressions never give rise to equal function objects. Each time
    * a function expression is evaluated, it creates a new closure value that
    * is not known to be equal to other closures created by the same expression.
    *
    * Classes implementing `Function` by having a `call` method should have their
    * own `operator==` and `hashCode` depending on the object.
    */
   bool operator ==(Object other);
 }