Fix potential bug with equation file in different dir

pysr/sr.py

@@ -439,7 +439,7 @@ migration={'true' if migration else 'false'},
 hofMigration={'true' if hofMigration else 'false'},
 fractionReplacedHof={fractionReplacedHof}f0,
 shouldOptimizeConstants={'true' if shouldOptimizeConstants else 'false'},
-hofFile="{equation_file}",
+hofFile="{_escape_filename(equation_file)}",
 npopulations={populations:d},
 nrestarts={nrestarts:d},
 perturbationFactor={perturbationFactor:f}f0,