doc/articles/gobs_of_data.html: delete extra word

Putt putt putt our way towards felicity.

R=golang-dev, bsiegert
CC=golang-dev
https://golang.org/cl/5874048

doc/articles/gobs_of_data.html

@@ -86,7 +86,7 @@ used to encode a protocol buffer, you might not be able to parse it.)
 First, protocol buffers only work on the data type we call a struct in Go. You
 can't encode an integer or array at the top level, only a struct with fields
 inside it. That seems a pointless restriction, at least in Go. If all you want
-to send is an array of integers, why should you have to put put it into a
+to send is an array of integers, why should you have to put it into a
 struct first?
 </p>