Make copy to clipboard in Windows error dialog include error message

There is a copy to clipboard option but the error itself wasn't printed
to the console so it wasn't copied to the clipboard.

Unix-like platforms print it to the console so it's written in
crashlog.txt.

code/sys/sys_win32.c

@@ -727,6 +727,8 @@ Display an error message
 */
 void Sys_ErrorDialog( const char *error )
 {
+	Sys_Print( va( "%s\n", error ) );
+
 	if( Sys_Dialog( DT_YES_NO, va( "%s. Copy console log to clipboard?", error ),
 			"Error" ) == DR_YES )
 	{