Function remove

src/fl/stl/unordered_map.h:542–550

remove key; returns true if removed

    // remove key; returns true if removed
    bool remove(const Key &key) {
        auto idx = find_index(key);
        if (idx == npos())
            return false;
        mark_deleted(idx);
        --_size;
        ++_tombstones;
        return true;
    }

    bool erase(const Key &key) { return remove(key); }