[Refactor] Refactor some stuff (#2688)

* fix some `internal` classes being exposed

* update xmldoc comments to use `<see langword>`

* bump library version in samples

* fix possible oversight

src/Discord.Net.Core/Logging/LogMessage.cs

@@ -33,7 +33,7 @@ namespace Discord
         ///     Gets the exception of this log entry.
         /// </summary>
         /// <returns>
-        ///     An <see cref="Discord.LogMessage.Exception" /> object associated with an incident; otherwise <c>null</c>.
+        ///     An <see cref="Discord.LogMessage.Exception" /> object associated with an incident; otherwise <see langword="null" />.
         /// </returns>
         public Exception Exception { get; }