Remove obsolete TODOs

Signed-off-by: Álvaro Brey <alvaro.brey@nextcloud.com>

app/src/main/java/com/owncloud/android/ui/preview/PreviewImageFragment.java

@@ -344,7 +344,6 @@ public class PreviewImageFragment extends FileFragment implements Injectable {
      * {@inheritDoc}
      */
     @Override
-    // TODO replace with MenuProvider
     public void onCreateOptionsMenu(@NonNull Menu menu, @NonNull MenuInflater inflater) {
         super.onCreateOptionsMenu(menu, inflater);
         inflater.inflate(R.menu.custom_menu_placeholder, menu);

app/src/main/java/com/owncloud/android/ui/preview/PreviewMediaFragment.java

@@ -375,7 +375,6 @@ public class PreviewMediaFragment extends FileFragment implements OnTouchListene
     }
 
     @Override
-    // TODO replace with MenuProvider
     public boolean onOptionsItemSelected(@NonNull MenuItem item) {
         if (item.getItemId() == R.id.custom_menu_placeholder_item) {
             final OCFile file = getFile();

app/src/main/java/com/owncloud/android/ui/preview/PreviewTextFileFragment.java

@@ -257,7 +257,6 @@ public class PreviewTextFileFragment extends PreviewTextFragment {
      * {@inheritDoc}
      */
     @Override
-    // TODO replace with MenuProvider
     public void onCreateOptionsMenu(@NonNull Menu menu, @NonNull MenuInflater inflater) {
         super.onCreateOptionsMenu(menu, inflater);
         inflater.inflate(R.menu.custom_menu_placeholder, menu);