docs(demos): remove attr from docs

ionic/components/app/id.ts

@@ -66,15 +66,7 @@ export class IdRef {
 
 
 /**
- * @name Attr
- * @description
- * Attr allows you to dynamically add or remove an attribute based on the value of an expression or variable.
- * @usage
- * ```html
- * // toggle the no-lines attributes based on whether isAndroid is true or false
- * <ion-list [attr.no-lines]="isAndroid ? '' : null">
- * ```
- * @demo /docs/v2/demos/attr/
+ * @private
  */
 @Directive({
   selector: '[attr]'