Fix typo in column_factories.hpp comment from 'depth 1' to 'depth 2' (r…

…apidsai#16700)

This PR fixes a typo in the `cpp/include/cudf/column/column_factories.hpp` file. The comment incorrectly mentioned "data (depth 1)" instead of "data (depth 2)". This correction improves code clarity and documentation accuracy.

Authors:
  - Hirota Akio (https://github.com/a-hirota)

Approvers:
  - David Wendt (https://github.com/davidwendt)
  - Nghia Truong (https://github.com/ttnghia)

URL: rapidsai#16700

cpp/include/cudf/column/column_factories.hpp

@@ -469,7 +469,7 @@ std::unique_ptr<column> make_strings_column(size_type num_strings,
  * offsets (depth 1)   {0, 2, 5, 7}
  * data    (depth 1)
  * offsets (depth 2)
- * data    (depth 1)   {1, 2, 3, 4, 5, 6, 7}
+ * data    (depth 2)   {1, 2, 3, 4, 5, 6, 7}
  * @endcode
  *
  * @param[in] num_rows The number of lists the column represents.