Replace (defunct) a-fwd links with direct amazon links

It'd be great if there was a more generic way to link to local bookstores, but
I haven't found it.

Author: marijnh

html/index.html

@@ -22,7 +22,7 @@
 <div id=cover>
 
   <p style="margin: 1em 0">
-    <a href="http://a-fwd.com/com=marijhaver-20&asin-com=1593279507">
+    <a href="https://www.amazon.com/gp/product/1593279507/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=1593279507&linkCode=as2&tag=marijhaver-20&linkId=d8642c0457954f03e27c02b0034d0d60">
       <img src="img/cover.jpg" alt="Cover image" style="border: 1px solid black; max-width: 100%; box-shadow: 4px 4px 7px rgba(0, 0, 0, 0.4)">
     </a>
   </p>
@@ -31,7 +31,7 @@ <h1>Eloquent JavaScript<div style="font-size: 70%">3rd edition</div></h2>
 
   <p>This is a book about JavaScript, programming, and the wonders of
   the digital. You can read it online here, or get your own
-  <a href="http://a-fwd.com/com=marijhaver-20&asin-com=1593279507">paperback
+  <a href="https://www.amazon.com/gp/product/1593279507/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=1593279507&linkCode=as2&tag=marijhaver-20&linkId=d8642c0457954f03e27c02b0034d0d60">paperback
   copy</a>.</p>
 
   <p>Written by Marijn Haverbeke.</p>