[minor] Fix deprecation warning

Add doc to fix `foo.coffee is using deprecated documentation syntax`

```
DEV banyan ☁  ./bin/hubot
Hubot> [Mon Jul 07 2014 19:15:31 GMT+0800 (PHT)] WARNING The HUBOT_AUTH_ADMIN environment variable not set
[Mon Jul 07 2014 19:15:31 GMT+0800 (PHT)] INFO /Users/banyan/quipper/quipper-hubot/scripts/assign.coffee is using deprecated documentation syntax
[Mon Jul 07 2014 19:15:31 GMT+0800 (PHT)] INFO /Users/banyan/quipper/quipper-hubot/scripts/media.coffee is using deprecated documentation syntax
[Mon Jul 07 2014 19:15:31 GMT+0800 (PHT)] INFO /Users/banyan/quipper/quipper-hubot/scripts/ps.coffee is using deprecated documentation syntax
[Mon Jul 07 2014 19:15:31 GMT+0800 (PHT)] INFO /Users/banyan/quipper/quipper-hubot/scripts/resque.coffee is using deprecated documentation syntax
[Mon Jul 07 2014 19:15:31 GMT+0800 (PHT)] INFO /Users/banyan/quipper/quipper-hubot/scripts/smoke.coffee is using deprecated documentation syntax
[Mon Jul 07 2014 19:15:31 GMT+0800 (PHT)] INFO Data for brain retrieved from Redis
```
https://github.com/github/hubot/blob/master/docs/scripting.md#documenting-scripts