fixed some TOODs

gallery/mplot3d/contour3d.cpp

 // example https://matplotlib.org/stable/gallery/mplot3d/contour3d.html
 
 #include <matplotlibcpp17/pyplot.h>
+#include <matplotlibcpp17/cm.h>
 
 #include <xtensor/xbuilder.hpp>
 #include <xtensor/xmath.hpp>
@@ -49,8 +50,7 @@ int main() {
   auto fig = plt.figure();
   auto ax = fig.add_subplot(Args(), Kwargs("projection"_a = "3d"));
   auto [X, Y, Z] = get_test_data(0.05);
-  // TODO: cmap=cm.coolwarm
-  ax.contour(Args(X, Y, Z));
+  ax.contour(Args(X, Y, Z), Kwargs("cmap"_a = cm::coolwarm()));
 #if USE_GUI
   plt.show();
 #else

gallery/mplot3d/surface3d.cpp

@@ -45,6 +45,10 @@ int main() {
                                      "linewidth"_a = 0, "antialiased"_a = false,
                                      "cmap"_a = cm::coolwarm()));
   ax.set_zlim(Args(-1.01, 1.01));
+  // TODO
+  // auto locator = ticker::LinearLocator(Args(10));
+  // ax.zaxis.set_major_locator(Args(locator.unwrap()));
+  // ax.zaxis.set_major_formatter(Args("{x:.02f}"));
   fig.colorbar(Args(surf), Kwargs("shrink"_a = 0.5, "aspect"_a = 5));
   plt.show();
 }