Add whatsnew entry for simple_efficiency zero load_loss bug

Author: aman-coder03

docs/sphinx/source/whatsnew/v0.14.0.rst

@@ -13,6 +13,18 @@ Breaking Changes
   in :py:func:`~pvlib.irradiance.haydavies`, :py:func:`~pvlib.irradiance.perez`,
   and :py:func:`~pvlib.irradiance.perez_driesse`. (:issue:`2529`, :pull:`2627`)
 
+
+Deprecations
+~~~~~~~~~~~~
+
+
+Bug fixes
+* Fixed a division-by-zero error in
+  :py:func:`pvlib.transformer.simple_efficiency` when ``load_loss = 0``.
+  (:issue:`2645`, :pull:`2646`)
+
+~~~~~~~~~
+
 Enhancements
 ~~~~~~~~~~~~
 * Add :py:func:`~pvlib.ivtools.sdm.fit_desoto_batzelis`, a function to estimate