[XAM/Net] Added note about sharing storage between Rtl and WSA errors

src/xenia/kernel/xam/xam_net.cc

@@ -288,6 +288,9 @@ dword_result_t NetDll_WSACleanup_entry(dword_t caller) {
 }
 DECLARE_XAM_EXPORT1(NetDll_WSACleanup, kNetworking, kImplemented);
 
+// Instead of using dedicated storage for WSA error like on OS.
+// Xbox shares space between normal error codes and WSA errors.
+// This under the hood returns directly value received from RtlGetLastError.
 dword_result_t NetDll_WSAGetLastError_entry() {
   return XThread::GetLastError();
 }