explanation of tab count

Signed-off-by: tobiasKaminsky <tobias@kaminsky.me>

app/src/main/java/com/owncloud/android/ui/adapter/FileDetailTabAdapter.java

@@ -71,9 +71,9 @@ public class FileDetailTabAdapter extends FragmentStatePagerAdapter {
     @Override
     public int getCount() {
         if (file.isEncrypted()) {
-            return 1;
+            return 1; // sharing not allowed for encrypted files, thus only show first tab (activities)
         } else {
-            return 2;
+            return 2; // show activities and sharing tab
         }
     }
 }