fix homebrew cask links

Author: williambelle

Apps/Octave.md

@@ -4,7 +4,7 @@
 
 ## Prerequisite
 
-You might need `homebrew-cask`; if you don't have it, refer to [this section](/Homebrew/Cask.html).
+You might need `homebrew-cask`; if you don't have it, refer to [this section](../Homebrew/Cask.md).
 
 ## Installation
 

Docker/README.md

@@ -18,7 +18,7 @@ Docker Toolbox is a legacy desktop solution for older Mac and Windows systems th
 
 ### Prerequisite
 
-You'll need `homebrew-cask` to install Docker Toolbox, if you don't have it refer to [this section](/mac-setup/Homebrew/Cask.html).
+You'll need `homebrew-cask` to install Docker Toolbox, if you don't have it refer to [this section](../Homebrew/Cask.md).
 
 ### Installation
 

Vagrant/README.md

@@ -4,7 +4,7 @@ Create and configure lightweight, reproducible, and portable development environ
 
 ## Prerequisite
 
-You'll need `homebrew-cask`, if you don't have it refer to [this section](/mac-setup/Homebrew/Cask.html).
+You'll need `homebrew-cask`, if you don't have it refer to [this section](../Homebrew/Cask.md).
 
 ## Installation