typo: node-sas -> node-sass

TROUBLESHOOTING.md

@@ -23,7 +23,7 @@ This document covers some common node-sass issues and how to resolve them. You s
 
 ### 404 downloading binding.node file
 
-If you see a 404 when trying to install node-sas, this indicates that your trying
+If you see a 404 when trying to install node-sass, this indicates that your trying
 to install a version of node-sass that doesn't support your verion of NodeJS, or
 uses an alternate V8 environment (Meteor, Electron, etc...) that isn't supported
 by node-sass.