Network[doc]: Update Qt6-changes with QNetworkInformation details

I always meant to remove the note and update it with a link, but forgot.

Qt 6.2 details only so it can be easily cherry-picked there.

Pick-to: 6.3 6.2
Change-Id: I4db3919b71971a997ac8a988951b01c984a8a791
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>

src/network/doc/src/qt6-changes.qdoc

@@ -88,8 +88,17 @@
     void networkSessionConnected();
     \endcode
 
-    \note Qt 6.0 does not provide replacements for these deleted
-    classes and functions.
+    QNetworkInformation, initially introduced in Qt 6.1, aims to replace some
+    aspects of the bearer management API. It works by providing a unified API
+    which subscribes to changes to the network as notified by the operating
+    system.
+
+    QNetworkInformation::reachability(), introduced in Qt 6.1, replaces the
+    QNetworkAccessManager::networkAccessible() function, while adding more
+    detailed information about the reachability of the network. See its
+    documentation for more details.
+
+    In Qt 6.2 QNetworkInformation gained the ability to detect captive portals.
 
     \section2 Deleted enumerators