finagle: Typo `ahere` changed to `adhere`
finagle: Typo `ahere` changed to `adhere`

Problem/Solution

There was a typo in finagle's contributing docs. @dainmiller fixed the typo.

Signed-off-by: Dorothy Ordogh <dordogh@twitter.com>

Closes twitter/finagle#895

Differential Revision: https://phabricator.twitter.biz/D645015

twitter/finagle,twitter/finagle,twitter/finagle,twitter/finagle,twitter/finagle