Fix voice channel typo

src/Discord.Net/Entities/Channels/ChannelType.cs

@@ -7,7 +7,7 @@
         Text = 0,
         ///<summary> A direct-message text channel </summary>
         DM = 1,
-        ///<summary> A voice channel channel </summary>
+        ///<summary> A voice channel </summary>
         Voice = 2,
         ///<summary> A group channel </summary>
         Group = 3