rn-18: link to discussion about Progit reedited

Author: tfnico

_posts/2016-08-17-edition-18.markdown

@@ -214,7 +214,7 @@ data along with their source code.
 
 __Various__
 
-* A ["Reedited" version](https://github.com/nobozo/progit2) of [*Pro Git 2nd Edition*](https://github.com/progit/progit2) by Jon Forrest
+* A ["Reedited" version](https://github.com/nobozo/progit2) of [*Pro Git 2nd Edition*](https://github.com/progit/progit2) by Jon Forrest (announcement and discussion on why reedited [here](https://public-inbox.org/git/[email protected]/))
 * Author of [git-annex](https://git-annex.branchable.com/), Joey Hess has [launched a Patreon page to support continued development on his open source projects](https://www.patreon.com/joeyh)
 
 __Light reading__