Format code with black

This commit fixes the style issues introduced in 5d9233a according to the output
from black.

Details: https://deepsource.io/gh/MilesCranmer/PySR/transform/a244ac16-0f75-4846-b65e-d1049d226249/

pysr/sr.py

@@ -1051,6 +1051,7 @@ def _run(self, X, y, weights, variable_names):
                 f'Pkg.activate("{_escape_filename(self.julia_project)}", io={io})'
             )
             from julia.api import JuliaError
+
             try:
                 if update:
                     Main.eval(f"Pkg.resolve(io={io})")