docs(changelog): add deprecation notice

- Add deprecation notice for `angular.lowercase` and `angular.uppercase`

Author: wesleycho

CHANGELOG.md

@@ -2028,6 +2028,7 @@ This version of AngularJS is problematic due to a issue during its release. Plea
 
 - The `ngTouch` module's `ngClick` directive has been deprecated and disabled by default. See the breaking
 changes section for more information
+- The `angular.lowercase` and `angular.uppercase` functions have been deprecated. It is recommended to use `String.prototype.toLowerCase` and `String.prototype.toUpperCase` functions instead.
 
 ## Bug Fixes
 

src/Angular.js

@@ -122,9 +122,33 @@ var REGEX_STRING_REGEXP = /^\/(.+)\/([a-z]*)$/;
 // This is used so that it's possible for internal tests to create mock ValidityStates.
 var VALIDITY_STATE_PROPERTY = 'validity';
 
+
 var hasOwnProperty = Object.prototype.hasOwnProperty;
 
+/**
+ * @ngdoc function
+ * @name angular.lowercase
+ * @module ng
+ * @kind function
+ * @deprecated
+ *
+ * @description Converts the specified string to lowercase.
+ * @param {string} string String to be converted to lowercase.
+ * @returns {string} Lowercased string.
+ */
 var lowercase = function(string) {return isString(string) ? string.toLowerCase() : string;};
+
+/**
+ * @ngdoc function
+ * @name angular.uppercase
+ * @module ng
+ * @kind function
+ * @deprecated
+ *
+ * @description Converts the specified string to uppercase.
+ * @param {string} string String to be converted to uppercase.
+ * @returns {string} Uppercased string.
+ */
 var uppercase = function(string) {return isString(string) ? string.toUpperCase() : string;};