DOC: fix missing quote in feather example

jorisvandenbossche · jorisvandenbossche · commit 975a440b08cc · 2016-12-29T01:27:24.000+01:00
diff --git a/doc/source/io.rst b/doc/source/io.rst
@@ -4198,7 +4198,7 @@ Write to a feather file.
 
 .. ipython:: python
 
-   df.to_feather('example.fth)
+   df.to_feather('example.fth')
 
 Read from a feather file.
 
