Merge pull request #6761 from Merott/hardware-typo

docs(platform): correct a minor typo of "hardware"

Author: brandyscarney

src/platform/platform.ts

@@ -317,7 +317,7 @@ export class Platform {
   * with a hardware back button in the same sense an Android or Windows device
   * does. It's important to note that this event does not emit when the Ionic
   * app's back button within the navbar is clicked, but this event is only
-  * referencing the platform's hardward back button.
+  * referencing the platform's hardware back button.
   */
   backButton: EventEmitter<Event> = new EventEmitter();