tdf#92269 fix Windows Explorer crash caused by shellextension

wcscpy_s is buffer size, not string length, so size must also account
for a terminating NULL

Change-Id: Ie69692e47c142f3b733b093d0b87fa4bb03db7b4
(cherry picked from commit 2279f1f0)
Reviewed-on: https://gerrit.libreoffice.org/16653Reviewed-by: Michael Stahl <mstahl@redhat.com>
Tested-by: Michael Stahl <mstahl@redhat.com>

shell/source/win32/shlxthandler/infotips/infotips.cxx

@@ -289,7 +289,7 @@ HRESULT STDMETHODCALLTYPE CInfoTip::GetInfoTip(DWORD /*dwFlags*/, wchar_t** ppws
 
         ZeroMemory(pMem, len);
 
-        wcscpy_s(pMem, msg.length(), msg.c_str());
+        wcscpy_s(pMem, msg.length()+1, msg.c_str());
 
         *ppwszTip = pMem;
         lpMalloc->Release();