Add missing period

Author: InvincibleRMC

include/pybind11/pytypes.h

@@ -116,7 +116,7 @@ class object_api : public pyobject_tag {
     /** \rst
          Similar to the above attr functions with the difference that the templated Type
          is used to set the `__annotations__` dict value to the corresponding key. Worth noting
-         that attr_with_type_hint is implemented in cast.h
+         that attr_with_type_hint is implemented in cast.h.
     \endrst */
     template <typename T>
     obj_attr_accessor attr_with_type_hint(handle key) const;