Rename norgate to nor_gate to keep consistency (#8968)

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

* updating DIRECTORY.md

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

Author: CaedenPH

DIRECTORY.md

@@ -62,7 +62,7 @@
 ## Boolean Algebra
   * [And Gate](boolean_algebra/and_gate.py)
   * [Nand Gate](boolean_algebra/nand_gate.py)
-  * [Norgate](boolean_algebra/norgate.py)
+  * [Nor Gate](boolean_algebra/nor_gate.py)
   * [Not Gate](boolean_algebra/not_gate.py)
   * [Or Gate](boolean_algebra/or_gate.py)
   * [Quine Mc Cluskey](boolean_algebra/quine_mc_cluskey.py)