Rename norgate to nor_gate to keep consistency (#8968)

* refactor(boolean-algebra): Rename norgate to nor_gate

* updating DIRECTORY.md

---------

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>

boolean_algebra/nor_gate.py

@@ -0,0 +1,48 @@
+"""
+A NOR Gate is a logic gate in boolean algebra which results to false(0)
+if any of the input is 1, and True(1) if  both the inputs are 0.
+Following is the truth table of a NOR Gate:
+   | Input 1 | Input 2 |  Output |
+   |      0      |     0      |      1      |
+   |      0      |     1      |      0      |
+   |      1      |     0      |      0      |
+   |      1      |     1      |      0      |
+
+Following is the code implementation of the NOR Gate
+"""
+
+
+def nor_gate(input_1: int, input_2: int) -> int:
+    """
+    >>> nor_gate(0, 0)
+    1
+    >>> nor_gate(0, 1)
+    0
+    >>> nor_gate(1, 0)
+    0
+    >>> nor_gate(1, 1)
+    0
+    >>> nor_gate(0.0, 0.0)
+    1
+    >>> nor_gate(0, -7)
+    0
+    """
+    return int(input_1 == input_2 == 0)
+
+
+def main() -> None:
+    print("Truth Table of NOR Gate:")
+    print("|   Input 1   |  Input 2  | Output |")
+    print(f"|      0      |    0      |  {nor_gate(0, 0)}     |")
+    print(f"|      0      |    1      |  {nor_gate(0, 1)}     |")
+    print(f"|      1      |    0      |  {nor_gate(1, 0)}     |")
+    print(f"|      1      |    1      |  {nor_gate(1, 1)}     |")
+
+
+if __name__ == "__main__":
+    import doctest
+
+    doctest.testmod()
+    main()
+"""Code provided by Akshaj Vishwanathan"""
+"""Reference: https://www.geeksforgeeks.org/logic-gates-in-python/"""