Revert "Deprecate the use of `Function` as a class."

pkg/analyzer/lib/src/dart/error/hint_codes.dart

Index: pkg/analyzer/lib/src/dart/error/hint_codes.dart
diff --git a/pkg/analyzer/lib/src/dart/error/hint_codes.dart b/pkg/analyzer/lib/src/dart/error/hint_codes.dart
index 72eb3ce34d08572809d68c78ab32edec1668db6f..a81585b3bc2a7d2b0be427e78eb5712e9785a377 100644
--- a/pkg/analyzer/lib/src/dart/error/hint_codes.dart
+++ b/pkg/analyzer/lib/src/dart/error/hint_codes.dart
@@ -95,30 +95,6 @@ class HintCode extends ErrorCode {
       "Try replacing the use of the deprecated member with the replacement.");
 
   /**
-   * Users should not create a class named `Function` anymore.
-   */
-  static const HintCode DEPRECATED_FUNCTION_CLASS_DECLARATION = const HintCode(
-      'DEPRECATED_FUNCTION_CLASS_DECLARATION',
-      "Declaring a class named 'Function' is deprecated.",
-      "Try renaming the class.");
-
-  /**
-   * `Function` should not be extended anymore.
-   */
-  static const HintCode DEPRECATED_EXTENDS_FUNCTION = const HintCode(
-      'DEPRECATED_EXTENDS_FUNCTION',
-      "Extending 'Function' is deprecated.",
-      "Try removing 'Function' from the 'extends' clause.");
-
-  /**
-   * `Function` should not be mixed in anymore.
-   */
-  static const HintCode DEPRECATED_MIXIN_FUNCTION = const HintCode(
-      'DEPRECATED_MIXIN_FUNCTION',
-      "Mixing in 'Function' is deprecated.",
-      "Try removing 'Function' from the 'with' clause.");
-
-  /**
    * Hint to use the ~/ operator.
    */
   static const HintCode DIVISION_OPTIMIZATION = const HintCode(