fix(voice): session id deadlock on open (#1408)

* Unlock when checking voice connection sessionID to prevent deadlock

* Move lock to preserve concurrency safety, while allowing the sessionID to be populated

* style: formatting

Fix formatting of the documentation comment for VoiceConnection.Speaking function

* feat: reword explanatory comment

---------

Co-authored-by: Fedor Lapshin <fe.lap.prog@gmail.com>

voice.go

@@ -76,7 +76,7 @@ type VoiceSpeakingUpdateHandler func(vc *VoiceConnection, vs *VoiceSpeakingUpdat
 // Speaking sends a speaking notification to Discord over the voice websocket.
 // This must be sent as true prior to sending audio and should be set to false
 // once finished sending audio.
-//  b  : Send true if speaking, false if not.
+// b : Send true if speaking, false if not.
 func (v *VoiceConnection) Speaking(b bool) (err error) {
 
 	v.log(LogDebug, "called (%t)", b)
@@ -294,11 +294,15 @@ func (v *VoiceConnection) open() (err error) {
 		if v.sessionID != "" {
 			break
 		}
+
 		if i > 20 { // only loop for up to 1 second total
 			return fmt.Errorf("did not receive voice Session ID in time")
 		}
+		// Release the lock, so sessionID can be populated upon receiving a VoiceStateUpdate event.
+		v.Unlock()
 		time.Sleep(50 * time.Millisecond)
 		i++
+		v.Lock()
 	}
 
 	// Connect to VoiceConnection Websocket