Update app.py

app.py

@@ -25,7 +25,7 @@ def highlight_diff(sent, sent_main):
     new_toks = []
     for i, (tok, tok_main) in enumerate(zip(tokens, tokens_main)):
         if tok != tok_main:
-            new_toks.append('\textcolor\{red\}\{**{}**\}'.format(tok))
+            new_toks.append('\textcolor{red}{**' + tok + '**}')
         else:
             new_toks.append(tok)