Doc: Suggest an alternative to connections with default params

The new signal-slot connection syntax does not support default
parameters. Lambda functions are a suitable replacement.

Change-Id: I906856104d582c1139c4b78b885566156c7f2f78
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>

doc/src/signalslotsyntaxes.qdoc

@@ -179,6 +179,10 @@ to QApplication::aboutToQuit(), even though the latter has no arguments. The
 functor-based connection will produce a compile-time error:
 \snippet snippets/signalsandslots/signalslotsyntaxes.cpp defaultparams
 
+To work around this limitation with the functor-based syntax, connect the signal to
+a lambda function that calls the slot. See the section above, \l{Making Connections
+to Lambda Expressions}.
+
 
 \section1 Selecting Overloaded Signals and Slots