Fix three memory leaks

Add documentation to BaseFragment.initViews(View, Bundle) and BaseFragment.initListeners()

app/src/main/java/org/schabi/newpipe/local/subscription/SubscriptionFragment.kt

@@ -115,6 +115,11 @@ class SubscriptionFragment : BaseStateFragment<SubscriptionState>() {
         feedGroupsCarouselState = feedGroupsCarousel.onSaveInstanceState()
     }
 
+    override fun onDestroyView() {
+        super.onDestroyView()
+        _binding = null
+    }
+
     override fun onDestroy() {
         super.onDestroy()
         disposables.dispose()