Revert "Update v0.12.1.rst"

This reverts commit e8a7b10.

Author: RDaxini

docs/sphinx/source/whatsnew/v0.12.1.rst

@@ -21,6 +21,8 @@ Enhancements
 * :py:mod:`pvlib.ivtools.sdm` is now a subpackage. (:issue:`2252`, :pull:`2256`)
 * Add a function for estimating PVsyst SDM parameters from IEC 61853-1 matrix
   data (:py:func:`~pvlib.ivtools.sdm.fit_pvsyst_iec61853_sandia_2025`). (:issue:`2185`, :pull:`2429`)
+* Add optional arguments `reference_temperature` and `reference_irradiance` to
+  :py:func:`~pvlib.pvsystem.sapm`(:issue:`2432`, :pull:`2434`)
 
 Documentation
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