Update the function hoisting external source

index.html

@@ -162,7 +162,7 @@
                             statusMessage.value = body
                           }
 
-                      Note that the `function` declarations here are defined at the bottom of the file. This is thanks to [function hoisting](https://gist.github.com/maxogden/4bed247d9852de93c94c).
+                      Note that the `function` declarations here are defined at the bottom of the file. This is thanks to [function hoisting](https://developer.mozilla.org/en-US/docs/Glossary/Hoisting).
 
                       ## 2. Modularize
 
@@ -225,7 +225,7 @@
                       ### Summary
 
                       1. Don't nest functions. Give them names and place them at the top level of your program
-                      2. Use [function hoisting](https://gist.github.com/maxogden/4bed247d9852de93c94c) to your advantage to move functions 'below the fold'
+                      2. Use [function hoisting](https://developer.mozilla.org/en-US/docs/Glossary/Hoisting) to your advantage to move functions 'below the fold'
                       3. Handle **every single error** in every one of your callbacks. Use a linter like [standard](http://standardjs.com/) to help you with this.
                       4. Create reusable functions and place them in a module to reduce the cognitive load required to understand your code. Splitting your code into small pieces like this also helps you handle errors, write tests, forces you to create a stable and documented  public API for your code, and helps with refactoring.