Update car.py

car.py

@@ -18,7 +18,7 @@ _CITATION = """
   title        = {{Car Evaluation}},
   year         = {1997},
   howpublished = {UCI Machine Learning Repository},
-  note         = {{DOI}: \url{10.24432/C5JP48}}
+  note         = {{DOI}: \\url{10.24432/C5JP48}}
 }
 """