Eliminate the need for bool operator>(unsigned long x1, const T x2)

This comparison operator was required in only one place.
Change this place to use operator> between T and T instead, like in most other places.

exprtk.hpp

@@ -24489,7 +24489,7 @@ namespace exprtk
                }
             }
 
-            if (vec_initilizer_list.size() > vector_size)
+            if (T(vec_initilizer_list.size()) > vector_size)
             {
                set_error(
                   make_error(parser_error::e_syntax,