fix(contourc): remove unused variable

Author: alandefreitas

source/matplot/util/contourc.cpp

@@ -396,12 +396,12 @@ namespace matplot {
 
                 const ContourLine::Children &children = line.get_children();
                 // number of points in the line itself
-                size_t npoints = static_cast<size_t>(line.size() + 1);
-                // accumulate the number of points for each line child
-                for (children_it = children.begin();
-                     children_it != children.end(); ++children_it) {
-                    npoints += static_cast<size_t>((*children_it)->size() + 1);
-                }
+                // size_t npoints = static_cast<size_t>(line.size() + 1);
+                // // accumulate the number of points for each line child
+                // for (children_it = children.begin();
+                //      children_it != children.end(); ++children_it) {
+                //     npoints += static_cast<size_t>((*children_it)->size() + 1);
+                // }
 
                 auto is_valid_point = [](double x, double y) {
                     return std::isfinite(x) && std::isfinite(y) && x != 0. &&