Suggested patch to handle syntax errors

[ghost]

Thank you for this excellent module!

I just have a suggestion: if there are any python syntax errors that occur during formatting, we currently simply get the message "Buffer is already yapfed". Instead of that, I believe it would be helpful to see these syntax errors. Therefore, I suggest this following patch, or something similar ...

--- py-yapf.el.orig	2017-11-18 12:36:18.017017290 -0500
+++ py-yapf.el	2017-11-18 12:36:27.086994492 -0500
@@ -139,7 +139,7 @@
         (if (zerop (call-process-region (point-min) (point-max) "diff" nil
                                         patchbuf nil "-n" "-" tmpfile))
             (progn
-              (kill-buffer errbuf)
+	      (switch-to-buffer errbuf)
               (pop kill-ring)
               (message (format "Buffer is already %sed" executable-name)))

What do you think?