First patch review - scoutapm PECL extension docs

Hi folks, Please could someone check my patch looks OK before I commit to it? I'm adding docs for the new scoutapm PECL extension. I've validated it with the local build tools already, and checked the documentation generated looks ok, but I'd appreciate someone just checking I've not made any breaking mistakes :) I've generated an svn diff and put it in a gist, please do let me know if there's anything else needed: https://gist.github.com/asgrim/d3f7e5c0cd5d396d323e06c065d8890e Thanks James