refactor(addon/components/-focusable): use better english.

addon/components/-focusable.js

@@ -17,7 +17,7 @@ import { action } from '@ember/object';
  *
  * Use the following as a base:
  * ```hbs
- * <myTag class='{{if this.focused " md-focused"}}' disabled={{this.disabled}} tabindex={{if this.disabled "-1" "0"}} {{did-insert this.registerListeners}} {{will-destroy this.unregisterListeners}} ...attributes>
+ * <myTag class='{{if this.focused " md-focused"}}' disabled={{this.disabled}} tabindex={{if this.disabled "-1" "0"}} {{did-insert this.registerListeners}} {{will-destroy this.deregisterListeners}} ...attributes>
  * </myTag>
  * ```
  */
@@ -68,7 +68,7 @@ export default class Focusable extends Component {
     });
   }
 
-  @action unregisterListeners(element) {
+  @action deregisterListeners(element) {
     element.removeEventListener('focusin', this.handleFocusIn);
     element.removeEventListener('focusout', this.handleFocusOut);
     element.removeEventListener('mousedown', this.handleMouseDown);