pidgin/nest

Add a blurb to the Contributing page to encourage people to look at open review requests.

Testing Done:
Ran development server and verified the page appeared as I expected.

Reviewed at https://reviews.imfreedom.org/r/819/
[![](/images/download.png)](https://sourceforge.net/projects/pidgin/files/Pidgin/{{ .Site.Params.currentVersion }}/pidgin-{{ .Site.Params.currentVersion}}{{ .Get 0 }})