message: Added a description
diff: namespace arangodb::velocypack {
  +/**
  + * @brief SharedSlice is similar to a Slice and has the same methods available.
  + * The difference is that SharedSlice owns the memory it points to (via a shared_ptr).
  + *
  + * All methods of Slice that return a Slice have an equivalent method here, but
  + * return a SharedSlice instead, which shares ownership of the same memory (but
  + * may point to a different location).
  + *
  + * Similarly, all methods of Slice that return a raw pointer have an equivalent
  + * method returning a shared_ptr, which also shares memory ownership with
  + * SharedSlice.
  + */
  class SharedSlice {
  public:
  explicit SharedSlice(std::shared_ptr<uint8_t const>&& data) noexcept;
  