editorial fix

git-svn-id: svn://bind10.isc.org/svn/bind10/branches/trac221b@2557 e5f2f494-b856-4b98-b285-d166d9295462

src/bin/auth/asio_link.h

@@ -30,7 +30,7 @@
 #include <exceptions/exceptions.h>
 
 namespace asio {
-// forward declaration forIOService::get_io_service() below
+// forward declaration for IOService::get_io_service() below
 class io_service;
 }