use same naming as clj solution

src/day7.cpp

@@ -76,13 +76,11 @@ void insert_or_increment(std::map<size_t, uint64_t> &cols, size_t col,
 uint64_t part_2(const Grid &grid) {
   Location start = find_start(grid);
   const auto [start_row, start_col]{start};
-  using namespace std::ranges::views;
-
   using namespace std::ranges;
   auto view = iota_view{start_row, grid.size()};
   std::map<size_t, uint64_t> starting_cols{{start_col, 1}};
-  auto cols = fold_left(view, starting_cols, [&grid](auto acc, auto row) {
+  auto cols = fold_left(view, starting_cols, [&grid](auto cols, auto row) {
-    return fold_left(acc, std::map<size_t, uint64_t>{},
+    return fold_left(cols, std::map<size_t, uint64_t>{},
                      [&grid, &row](auto next_cols, auto col_cnt) {
                        auto [col, cnt] = col_cnt;
                        if (at_loc(grid, row, col) == '^') {