docs(ngModel): fix contenteditable description

contenteditable is supported in many more browsers than Angular itself is.

http://caniuse.com/#feat=contenteditable

Closes angular#11172

Author: jkjustjoshing

src/ng/directive/ngModel.js

@@ -129,8 +129,8 @@ is set to `true`. The parse error is stored in `ngModel.$error.parse`.
  * data-binding. Notice how different directives (`contenteditable`, `ng-model`, and `required`)
  * collaborate together to achieve the desired result.
  *
- * Note that `contenteditable` is an HTML5 attribute, which tells the browser to let the element
- * contents be edited in place by the user.  This will not work on older browsers.
+ * `contenteditable` is an HTML5 attribute, which tells the browser to let the element
+ * contents be edited in place by the user.
  *
  * We are using the {@link ng.service:$sce $sce} service here and include the {@link ngSanitize $sanitize}
  * module to automatically remove "bad" content like inline event listener (e.g. `<span onclick="...">`).