docs: Enhance documentation for AddGroup with detailed brief and type parameter description

Author: weilycoder

weilycoder/ds/group.hpp

@@ -1,6 +1,10 @@
 #ifndef WEILYCODER_GROUP_HPP
 #define WEILYCODER_GROUP_HPP
 
+/**
+ * @brief Additive Group
+ * @tparam T Type of the elements
+ */
 template <typename T> struct AddGroup {
   using value_type = T;
   static constexpr T operation(const T &a, const T &b) { return a + b; }