Format code with black

This commit fixes the style issues introduced in 6db5312 according to the output
from black.

Details: https://deepsource.io/gh/MilesCranmer/PySR/transform/e512c949-ba2c-45b0-aba5-d650dc503c30/

pysr/sr.py

@@ -741,7 +741,6 @@ class PySRRegressor(MultiOutputMixin, RegressorMixin, BaseEstimator):
         julia_kwargs=None,
         **kwargs,
     ):
-
         # Hyperparameters
         # - Model search parameters
         self.model_selection = model_selection
@@ -2095,7 +2094,6 @@ class PySRRegressor(MultiOutputMixin, RegressorMixin, BaseEstimator):
         equation_file_contents = copy.deepcopy(self.equation_file_contents_)
 
         for output in equation_file_contents:
-
             scores = []
             lastMSE = None
             lastComplexity = 0