VoiceReceiverAdapter.java: add default missing doc

Signed-off-by: Chris Sdogkos <work@chris-sdogkos.com>

Author: christolis

application/src/main/java/org/togetherjava/tjbot/features/VoiceReceiverAdapter.java

@@ -8,6 +8,9 @@
 
 import java.util.regex.Pattern;
 
+/**
+ * Default implementation of {@link VoiceReceiver}.
+ */
 public class VoiceReceiverAdapter implements VoiceReceiver {
 
     private final Pattern channelNamePattern;