Improve IPC documentation

Fixes done:
- Mention missing QLocalServer/Socket
- Update Session Management information since it has been fixed and
implemented for all desktop OSs

Change-Id: Ib90965dc60afe051631c01ccf2078f300052a520
Reviewed-by: Paul Wicking <paul.wicking@qt.io>
Reviewed-by: Sze Howe Koh <szehowe.koh@gmail.com>

doc/src/frameworks-technologies/ipc.qdoc

@@ -38,11 +38,19 @@
 
     The cross-platform \l{Qt Network} module provides classes that make
     network programming portable and easy. It offers high-level
-    classes (e.g., QNetworkAccessManager, QFtp) that communicate using
+    classes (e.g. QNetworkAccessManager) that communicate using
     specific application-level protocols, and lower-level classes
     (e.g., QTcpSocket, QTcpServer, QSslSocket) for implementing
     protocols.
 
+    \section1 Local Server/Socket
+
+    The cross-platform \l{Qt Network} module provides classes that make
+    local network programming portable and easy. It offers the QLocalServer
+    and QLocalSocket classes that allow for network-like communication in a
+    local setup. Their TCP counterparts can be used as drop-in replacement to
+    make the communication work across networks.
+
     \section1 Shared Memory
 
     The cross-platform shared memory class, QSharedMemory, provides
@@ -72,10 +80,10 @@
 
     \section1 Session Management
 
-    In Linux/X11 platforms, Qt provides support for session management.
-    Sessions allow events to be propagated to processes, for example, to
-    notify when a shutdown occurs. The process and applications can then
-    perform any necessary operations such as save open documents.
+    On Linux/X11, Windows and macOS, Qt provides support for session
+    management. Sessions allow events to be propagated to processes, for
+    example, to notify when a shutdown occurs. The process and applications
+    can then perform any necessary operations such as save open documents.
 
     \list
     \li \l{Session Management}