Fix type errors in compiler and tests.

In preparation for a float32 build of MuJoCo.

PiperOrigin-RevId: 644407674
Change-Id: I60069f0f865ef89fbf613f5a2ca0c336cc63461e

plugin/sdf/nut.cc

@@ -148,7 +148,7 @@ void Nut::RegisterPlugin() {
     delete reinterpret_cast<Nut*>(d->plugin_data[instance]);
     d->plugin_data[instance] = 0;
   };
-  plugin.reset = +[](const mjModel* m, double* plugin_state, void* plugin_data,
+  plugin.reset = +[](const mjModel* m, mjtNum* plugin_state, void* plugin_data,
                      int instance) {
     auto sdf = reinterpret_cast<Nut*>(plugin_data);
     sdf->Reset();