Auto merge of #4237 - vignesh-sankaran:blacklist-url-doc, r=carols10cents
authorbors <bors@rust-lang.org>
Thu, 3 Aug 2017 15:01:06 +0000 (15:01 +0000)
committerbors <bors@rust-lang.org>
Thu, 3 Aug 2017 15:01:06 +0000 (15:01 +0000)
Added documentation blacklisting notes

Added notes regarding [documentation domain blacklisting](https://github.com/rust-lang/crates.io/issues/626) on crates.io


Trivial merge