Mark REST helper classes as tech preview

Task-number: QTBUG-119002
Change-Id: Icf4d50b0e6f25e4e5f82df0b23a249332bbf55bf
Reviewed-by: Marc Mutz <marc.mutz@qt.io>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>

src/network/access/qnetworkrequestfactory.cpp

@@ -27,6 +27,8 @@ Q_LOGGING_CATEGORY(lcQrequestfactory, "qt.network.access.request.factory")
     \brief Convenience class for grouping remote server endpoints that share
     common network request properties.
 
+    \preliminary
+
     REST servers often have endpoints that require the same headers and other data.
     Grouping such endpoints with a QNetworkRequestFactory makes it more
     convenient to issue requests to these endpoints; only the typically

src/network/access/qrestaccessmanager.cpp

@@ -35,6 +35,8 @@ Q_LOGGING_CATEGORY(lcQrest, "qt.network.access.rest")
     \inmodule QtNetwork
     \reentrant
 
+    \preliminary
+
     QRestAccessManager provides a networking API for typical REST client
     applications. It provides the means to issue HTTP requests such as GET
     and POST. The responses to these requests can be handled with traditional

src/network/access/qrestreply.cpp

@@ -26,6 +26,8 @@ Q_DECLARE_LOGGING_CATEGORY(lcQrest)
     \ingroup network
     \inmodule QtNetwork
 
+    \preliminary
+
     QRestReply is a convenience class for typical RESTful client
     applications. It wraps the more detailed QNetworkReply and provides
     convenience methods for data and status handling.