DOC: to_json (pandas-dev#17461)

Author: majiang

pandas/core/generic.py

@@ -1265,7 +1265,7 @@ def to_json(self, path_or_buf=None, orient=None, date_format=None,
         Parameters
         ----------
         path_or_buf : the path or buffer to write the result string
-            if this is None, return a StringIO of the converted string
+            if this is None, return the converted string
         orient : string
 
             * Series