Doc: Remove redundant \code

The preceding snippet contains the same line of code. It is unclear
why this line is repeated, and it does not seem to serve a purpose.
This patch removes the line of code and the QDoc command used to set
it apart from the preceding snippet.

Task-number: QTBUG-56772
Change-Id: I400b22aa75ee4542bfb67f7e47e3c31c577a39e5
Reviewed-by: Martin Smith <martin.smith@qt.io>

src/widgets/kernel/qaction.cpp

@@ -232,10 +232,6 @@ void QActionPrivate::setShortcutEnabled(bool enable, QShortcutMap &map)
     the action. For example:
 
     \snippet mainwindows/application/mainwindow.cpp 19
-    \codeline
-    \code
-    fileMenu->addAction(openAct);
-    \endcode
 
     We recommend that actions are created as children of the window
     they are used in. In most cases actions will be children of