add note regarding array shape

Author: kandersolar

pvlib/ivtools/sdm/pvsyst.py

@@ -402,6 +402,9 @@ def fit_pvsyst_iec61853_sandia_2025(effective_irradiance, temp_cell,
 
     Notes
     -----
+    Input arrays of operating conditions and electrical measurements must be
+    1-D with equal lengths.
+    
     This method is non-iterative.  In some cases, it may be desirable to
     refine the estimated parameter values using a numerical optimizer like
     those provided in ``scipy.optimize``.