[Suggestion] Properties vs Class variables

```objc
@interface DoxDialerCaller() {
NSURL *_dialerSchemeURL;
NSURL *_openDialerInAppStoreURL;
UIImage *_dialerIcon;
UIImage *_dialerIconAsTemplate;
}
```

While I like class variables I believe the use o `_` before the name can be misleading because the "convention" is to name `properties` in this way.

Locate the DoxDialerCaller implementation containing the shown anonymous interface and inspect how these instance variables are referenced and distinguished from properties. Decide on a consistent naming convention, update the affected references if the project agrees, and verify that the project still builds.

Written by the indexing model from the issue text.