Fix link rot for "What is Gradual Typing?" article (#2009)

Author: detuur

lang-guide/chapters/types/00_types_overview.md

@@ -7,4 +7,4 @@ Nu is strongly typed and gradually typed.
 - **Strongly typed:** Types are strictly enforced.
 - **Gradually typed:** A mix between static (types are checked at compile time) type checks and dynamic (types are checked at runtime).
 
-  Gradual typing is a clarification of optional typing where the developer could choose or not choose to add type annotations to declarations. This paper from Jeremy Siek is here: [What is Gradual Typing?](https://wphomes.soic.indiana.edu/jsiek/what-is-gradual-typing/)
+  Gradual typing is a clarification of optional typing where the developer could choose or not choose to add type annotations to declarations. This paper from Jeremy Siek is here: [What is Gradual Typing?](https://jsiek.github.io/home/WhatIsGradualTyping.html)