Point to docs.brew.sh (Homebrew#29296)

CONTRIBUTING.md

@@ -55,7 +55,7 @@ $ git remote add "$github_user" "https://github.com/$github_user/homebrew-cask"
 
 ## Adding a Cask
 
-Notice an application that's not in Homebrew-Cask yet? Make sure it's not yet in [Homebrew-Versions](https://github.com/caskroom/homebrew-versions) (can be searched from the Github repository page) or [Homebrew](https://github.com/Homebrew/homebrew) (can be searched with `brew search`). Mac App Store apps can't be installed via Homebrew-Cask, but check out [mas](https://github.com/argon/mas) for an alternative.
+Notice an application that's not in Homebrew-Cask yet? Make sure it's not yet in [Caskroom/versions](https://github.com/caskroom/homebrew-versions) or [Homebrew/core](https://github.com/Homebrew/homebrew-core) (can be searched with `brew search`). Mac App Store apps can't be installed via Homebrew-Cask, but check out [mas](https://github.com/argon/mas) for an alternative.
 
 With a bit of work, you can create a Cask for it. [This document](doc/development/adding_a_cask.md) will walk you through creating a new Cask, testing it, and submitting it to us.
 

README.md

@@ -6,7 +6,7 @@ Homebrew-Cask extends [Homebrew](http://brew.sh) and brings its elegance, simpli
 
 We do this by providing a friendly Homebrew-style CLI workflow for the administration of macOS applications distributed as binaries.
 
-It’s implemented as a `homebrew` [external command](https://github.com/Homebrew/brew/blob/master/docs/External-Commands.md) called `cask`.
+It’s implemented as a `homebrew` [external command](http://docs.brew.sh/External-Commands.html) called `cask`.
 
 [![Build Status](https://img.shields.io/travis/caskroom/homebrew-cask/master.svg)](https://travis-ci.org/caskroom/homebrew-cask)
 [![Join the chat at https://gitter.im/caskroom/homebrew-cask](https://img.shields.io/badge/gitter-join%20chat-blue.svg)](https://gitter.im/caskroom/homebrew-cask)