Doc: Fix incorrect usage of \generatelist

The \generatelist command takes an optional argument
that affect how the members are listed, for example,
`classesbymodule` which creates an annotated list of
the classes in a named C++ module.

`groupsbymodule` is not recognized or documented. QDoc
falls back to generating a list of all members of a
group in this case. While the end result is correct,
this relies on an undocumented feature that is likely
to change and break.

Replace these instances with an explicit \annotatedlist
command that produces the same output.

Pick-to: 6.10
Task-number: QTBUG-138901
Change-Id: I0c23dac38445e41940907cf32a6da6fe3b769f7f
Reviewed-by: Paul Wicking <paul.wicking@qt.io>

src/coap/doc/src/qtcoap-index.qdoc

@@ -67,5 +67,5 @@
     In addition, it is available under the
     \l{GNU General Public License, version 3}.
 
-    \generatelist{groupsbymodule attributions-qtcoap}
+    \annotatedlist attributions-qtcoap
 */