Support showing connected device in repeater tile

mobile/src/main/java/be/mygod/vpnhotspot/util/KillableTileService.kt

@@ -2,7 +2,9 @@ package be.mygod.vpnhotspot.util
 
 import android.content.ComponentName
 import android.content.ServiceConnection
+import android.os.Build
 import android.os.IBinder
+import android.service.quicksettings.Tile
 import android.service.quicksettings.TileService
 import androidx.annotation.RequiresApi
 
@@ -10,6 +12,13 @@ import androidx.annotation.RequiresApi
 abstract class KillableTileService : TileService(), ServiceConnection {
     protected var tapPending = false
 
+    /**
+     * Compat helper for setSubtitle.
+     */
+    protected fun Tile.subtitle(value: CharSequence?) {
+        if (Build.VERSION.SDK_INT >= 29) subtitle = value
+    }
+
     override fun onServiceConnected(name: ComponentName?, service: IBinder?) {
         if (tapPending) {
             tapPending = false