extend doc comment for ISuperCoolFeatures

polymorphism/include/polymorphism/i_super_cool_features.hpp

@@ -6,6 +6,12 @@
 namespace classic {
 
 /// @brief A typical interface definition via a class with pure virtual functions/methods.
+///
+/// This interface demonstrates classic polymorphism in C++.
+///
+/// @details
+/// - coolFeature(): Returns a string representing some cool feature.
+/// - set(std::string s): Sets some internal state of the implementing class.
 class ISuperCoolFeatures {
 public:
     [[nodiscard]] virtual std::string coolFeature() const = 0; // Pure virtual function