Add missing '<'

Change-Id: I86a01f0a066a915b9f87768fc73d24ab2fcdb4f6
Reviewed-on: https://gerrit.libreoffice.org/15182Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

configure.ac

@@ -2034,7 +2034,7 @@ AC_ARG_WITH(windows-sdk,
          combinations are supported. The intent is that this option should not
          be needed.])
     [
-                          Usage:     --with-windows-sdk=7.1(A)/8.0(A)/8.1(A)>
+                          Usage:     --with-windows-sdk=<7.1(A)/8.0(A)/8.1(A)>
     ],
 ,)