docs(forms): remove redundant call to $scope.$apply()

As of Angular 1.3 `$setViewValue` already calls `$apply` and triggers a
digest cycle, so now there is no need wrapping the `$setViewValue`
function call with `$apply`, which will just trigger an additional digest
cycle.

Author: noynir

docs/content/guide/forms.ngdoc

@@ -491,9 +491,7 @@ The following example shows how to add two-way data-binding to contentEditable e
         link: function(scope, elm, attrs, ctrl) {
           // view -> model
           elm.on('blur', function() {
-            scope.$apply(function() {
               ctrl.$setViewValue(elm.html());
-            });
           });
 
           // model -> view