Use the recommended TRUE value for AfxConnectionAdvise/Unadvise

In MicrosoftDocs/cpp-docs-pr#4999 we recommended
using TRUE but failed to update the sample to follow the recommendation.

Author: oldnewthing

docs/mfc/codesnippet/CPP/connection-maps_3.cpp

@@ -10,4 +10,4 @@ IUnknown* pUnkSink = mysink.GetInterface(&iid);
 //pUnkSrc is IUnknown of server obtained by CoCreateInstance().
 //dwCookie is a cookie identifying the connection, and is needed
 //to terminate this connection.
-AfxConnectionAdvise(pUnkSrc, IID_ISampleSink, pUnkSink, FALSE, &dwCookie);
+AfxConnectionAdvise(pUnkSrc, IID_ISampleSink, pUnkSink, TRUE, &dwCookie);

docs/mfc/codesnippet/CPP/connection-maps_4.cpp

@@ -6,4 +6,4 @@ IUnknown* pUnkSink = mysink.GetInterface(&iid);
 //Terminate a connection between source and sink.
 //pUnkSrc is IUnknown of server obtained by CoCreateInstance().
 //dwCookie is a value obtained through AfxConnectionAdvise().
-AfxConnectionUnadvise(pUnkSrc, IID_ISampleSink, pUnkSink, FALSE, dwCookie);
+AfxConnectionUnadvise(pUnkSrc, IID_ISampleSink, pUnkSink, TRUE, dwCookie);