Return negative position when there is no track

Also coerce position up to the length

core/src/commonMain/kotlin/dev/schlaubi/lavakord/audio/internal/WebsocketPlayer.kt

@@ -29,10 +29,11 @@ internal class WebsocketPlayer(internal val node: NodeImpl, internal val guildId
     private var updateTime: Instant = Instant.DISTANT_PAST
     override val positionDuration: Duration
         get() {
+            val trackLength = playingTrack?.info?.length?.milliseconds ?: return (-1).milliseconds
             val now = Clock.System.now()
             val elapsedSinceUpdate = now - updateTime
 
-            return lastPosition + elapsedSinceUpdate
+            return (lastPosition + elapsedSinceUpdate).coerceAtMost(trackLength)
         }
 
     override val volume: Int

core/src/commonMain/kotlin/dev/schlaubi/lavakord/audio/player/Player.kt

@@ -18,8 +18,10 @@ import kotlin.time.DurationUnit
  * @property playingTrack the currently playing [Track]
  * @property paused whether the playback is currently paused or not
  * @property volume the current volume of this player
- * @property position the position of the current song the player is at (-1 if [playingTrack] is null)
- * @property positionDuration the position of the current song the player is at (-1 if [playingTrack] is null)
+ * @property position the position of the current song the player is at (or negative if [playingTrack] is null).
+ * Capped at the track length.
+ * @property positionDuration the position of the current song the player is at (or negative if [playingTrack] is null).
+ * Capped at the track length.
  * @property equalizers the applied equalizers in this player
  */
 public interface Player : EventSource<Event> {