message: docs(button): fix icon usage
diff: @@ -358,17 +358,17 @@ export class ButtonExample {
  <!-- Icons -->
  <ion-button>
  - <ion-icon slot="start" name="star"></ion-icon>
  + <ion-icon slot="start" :icon="star"></ion-icon>
  Left Icon
  </ion-button>
  <ion-button>
  Right Icon
  - <ion-icon slot="end" name="star"></ion-icon>
  + <ion-icon slot="end" :icon="star"></ion-icon>
  </ion-button>
  <ion-button>
  - <ion-icon slot="icon-only" name="star"></ion-icon>
  + <ion-icon slot="icon-only" :icon="star"></ion-icon>
  </ion-button>
  <!-- Sizes -->
  @@ -378,11 +378,15 @@ export class ButtonExample {
  </template>
  <script>
  -import { IonButton } from '@ionic/vue';
  +import { IonButton, IonIcon } from '@ionic/vue';
  import { defineComponent } from 'vue';
  +import { star } from 'ionicons/icons';
  export default defineComponent({
  - components: { IonButton }
  + components: { IonButton, IonIcon },
  + setup() {
  + return { star }
  + }
  });
  </script>
  ```
  