Drop unused typedef

Change-Id: I2bc18d48ebf4401d9af576fb1b98b69ff44ab334
Reviewed-on: https://gerrit.libreoffice.org/20485Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: David Tardon <dtardon@redhat.com>

starmath/source/ElementsDockingWindow.cxx

@@ -29,8 +29,6 @@
 #include <sfx2/sfxmodelfactory.hxx>
 #include <vcl/settings.hxx>
 
-typedef tools::SvRef<SmDocShell> SmDocShellRef;
-
 SmElement::SmElement(SmNodePointer pNode, const OUString& aText, const OUString& aHelpText) :
     mpNode(pNode),
     maText(aText),