Haskell: Fix missing include

..when building with Qt6.2.

Change-Id: I224feb4ee8d658ffa2702c0a111c5390c0a80f1a
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/haskell/haskelleditorfactory.cpp

@@ -16,6 +16,8 @@
 #include <texteditor/texteditoractionhandler.h>
 #include <texteditor/textindenter.h>
 
+#include <QAction>
+
 using namespace TextEditor;
 
 namespace Haskell::Internal {