Fix typo in class documentation (#71)

* 0.5.6

* fix typo

Co-authored-by: Jakob Möller <jakob.moeller@sap.com>
Co-authored-by: marcmuschko <marc.muschko@sap.com>

Corona-Warn-App/src/main/java/de/rki/coronawarnapp/ui/main/MainFragment.kt

@@ -23,7 +23,7 @@ import de.rki.coronawarnapp.util.OpenUrlHelper
 
 /**
  * After the user has finished the onboarding this fragment will be the heart of the application.
- * Two VieModels are needed that this fragment shows all relevant information to the user.
+ * Two ViewModels are needed that this fragment shows all relevant information to the user.
  * Also the Menu is set here.
  *
  * @see tracingViewModel