Update private API documentation

mobile/src/main/java/be/mygod/vpnhotspot/net/TetherType.kt

@@ -48,7 +48,7 @@ enum class TetherType {
         @RequiresApi(30)
         private fun updateRegexs() {
             requiresUpdate = false
-            val tethering = TetheringManager.PACKAGE to app.packageManager.getResourcesForApplication(
+            val tethering = "com.android.networkstack.tethering" to app.packageManager.getResourcesForApplication(
                     TetheringManager.resolvedService.serviceInfo.applicationInfo)
             usbRegexs = tethering.getRegexs("config_tether_usb_regexs")
             wifiRegexs = tethering.getRegexs("config_tether_wifi_regexs")

mobile/src/main/java/be/mygod/vpnhotspot/net/TetheringManager.kt

@@ -63,9 +63,6 @@ object TetheringManager {
     @RequiresApi(30)
     const val TETHERING_SERVICE = "tethering"
 
-    @RequiresApi(30)
-    const val PACKAGE = "com.android.networkstack.tethering"
-
     @RequiresApi(30)
     private const val TETHERING_CONNECTOR_CLASS = "android.net.ITetheringConnector"
 
@@ -287,14 +284,8 @@ object TetheringManager {
                 if (args.isNotEmpty()) Timber.w("Unexpected args for ${method.name}: $args")
                 @Suppress("NAME_SHADOWING") val callback = reference.get()
                 when (method.name) {
-                    "onTetheringStarted" -> {
-                        callback?.onTetheringStarted()
-                        null
-                    }
-                    "onTetheringFailed" -> {
-                        callback?.onTetheringFailed()
-                        null
-                    }
+                    "onTetheringStarted" -> callback?.onTetheringStarted()
+                    "onTetheringFailed" -> callback?.onTetheringFailed()
                     else -> ProxyBuilder.callSuper(proxy, method, args)
                 }
             }