Remove ASIO_ENABLE_OLD_SERVICES from documentation.
diff --git a/asio/src/doc/using.qbk b/asio/src/doc/using.qbk
index 8ffa11d..81f509e 100644
--- a/asio/src/doc/using.qbk
+++ b/asio/src/doc/using.qbk
@@ -292,16 +292,6 @@
         the map.
     ]
   ]
-  [
-    [`ASIO_ENABLE_OLD_SERVICES`]
-    [
-      The service template parameters, and the corresponding classes, are
-      disabled by default. For example, instead of `basic_socket<Protocol,
-      SocketService>` we now have simply `basic_socket<Protocol>`. The old
-      interface can be enabled by defining the `ASIO_ENABLE_OLD_SERVICES`
-      macro.
-    ]
-  ]
 ]
 
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