updating DIRECTORY.md

Author: pre-commit-ci[bot]

Diff for: DIRECTORY.md

@@ -289,6 +289,7 @@
     * [Dijkstras Two Stack Algorithm](data_structures/stacks/dijkstras_two_stack_algorithm.py)
     * [Infix To Postfix Conversion](data_structures/stacks/infix_to_postfix_conversion.py)
     * [Infix To Prefix Conversion](data_structures/stacks/infix_to_prefix_conversion.py)
+    * [Largest Rectangle Histogram](data_structures/stacks/largest_rectangle_histogram.py)
     * [Lexicographical Numbers](data_structures/stacks/lexicographical_numbers.py)
     * [Next Greater Element](data_structures/stacks/next_greater_element.py)
     * [Postfix Evaluation](data_structures/stacks/postfix_evaluation.py)