Insertion Sort

#include <concepts>
#include <vector>

namespace mehara::sort {
template <typename T>
requires std::totally_ordered<T>
void insertion_sort(std::vector<T>& array){
  for (auto outer_index = 1; outer_index < array.size(); outer_index++) {
    auto key = array[outer_index];
    auto inner_index = outer_index - 1;
    while (inner_index >= 0 && array[inner_index] > key) {
      array[inner_index + 1] = array[inner_index];
      inner_index = inner_index - 1;
    }
    array[inner_index + 1] = key;
  }
}
}