Update app.py

app.py

@@ -458,7 +458,7 @@ if __name__=='__main__':
     output: the predicted Rf value.\n\n
     ## Citation\n
     We would appreciate it if you use our software and give us credit in the acknowledgements section of your paper:\n
-    we use RF prediction software in our synthesis work. [Citation 1, Citation 2]
+    we use RF prediction software in our synthesis work. [Citation 1, Citation 2]\n
     Citation1: H. Xu, J. Lin, Q. Liu, Y. Chen, J. Zhang, Y. Yang, M.C. Young, Y. Xu, D. Zhang, F. Mo
     High-throughput discovery of chemical structure-polarity relationships combining automation and machine-learning techniques
     Chem (2022), 3202–3214, 10.1016/j.chempr.2022.08.008\n