A fixed capacity vector, or a variable length array for c++20, for dynamic arrays of maximum known size

Implements most of vector functions except those dealing with resizing.

Notes: Size doesn't necessarily need it's own particular address relative to the internal array, technically it may be placed in front or behind the array. If not being passed around it could even be completely disconnected.

In this implementation I chose in front, this may lose in terms of memory size / layout for large types.

The default error handling behavior eaither noop's or saturates capacity when insertions are too large.

Given a known size at compile time it may be handy to have a few extra tools available for inserting and appending data.

        // shove_back's (unchecked_push_back)
        constexpr void shove_back(const T &value);
        constexpr void shove_back(T &&value);
        template <class... Args> constexpr reference unchecked_emplace_back(Args &&... args);

        void append(size_type count, const T &value);
        template <typename some_iterator> void append(some_iterator first, some_iterator last);