Update qiskit_experiments/curve_analysis/fit_models.py

Co-authored-by: Daniel J. Egger <38065505+eggerdj@users.noreply.github.com>

Author: nkanazawa1989

qiskit_experiments/curve_analysis/fit_models.py

@@ -108,9 +108,9 @@ def __init__(
             fit_models = [fit_models]
         self._fit_models = fit_models
 
-        # Create signature of this fit model, i.e. this will be signature of scipy fit function.
-        # The curves comprising this model may have different signatures.
-        # The signature of this fit model is union of parameters in all curves.
+        # Create the signature of the fit model, i.e. the signature of `__call__` for scipy.
+        # The individual curves comprising this model may have different signatures.
+        # The signature of this fit model is the union of the parameters in all curves.
         # This is order preserving since this affects the index of ``popt`` that scipy fitter
         # returns, which appears as @Parameters entry of curve analysis as-is.
         union_params = []