Removed duplicated include

Change-Id: I052762267bee88789e88b1b2f7ecabc192620a45
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/94877
Tested-by: Jenkins
Reviewed-by: Julien Nabet <serval2412@yahoo.fr>
diff --git a/sw/source/filter/ww8/docxattributeoutput.cxx b/sw/source/filter/ww8/docxattributeoutput.cxx
index 4108c92..b06cd14 100644
--- a/sw/source/filter/ww8/docxattributeoutput.cxx
+++ b/sw/source/filter/ww8/docxattributeoutput.cxx
@@ -143,7 +143,6 @@
#include <stdarg.h>

#include <toolkit/helper/vclunohelper.hxx>
#include <oox/mathml/export.hxx>

using ::editeng::SvxBorderLine;