content: fix double-underscore typo in defer-panic-recover article

The typo produces an underscore “[…]order after_the surrounding[…]” at
http://blog.golang.org/defer-panic-and-recover

Change-Id: I0ab9be9cbef772c3ebff684e7de96fc4c2c802c6
Reviewed-on: https://go-review.googlesource.com/16477
Reviewed-by: Minux Ma <minux@golang.org>
1 file changed