updating DIRECTORY.md

Author: MRJPEREZR

DIRECTORY.md

@@ -422,7 +422,6 @@
   * [Resistor Color Code](electronics/resistor_color_code.py)
   * [Resistor Equivalence](electronics/resistor_equivalence.py)
   * [Resonant Frequency](electronics/resonant_frequency.py)
-  * [Star Delta Transform](electronics/star_delta_transform.py)
   * [Wheatstone Bridge](electronics/wheatstone_bridge.py)
 
 ## File Transfer