Fix typo in errata

Author: marijnh

html/errata.html

@@ -32,7 +32,7 @@ <h2>Chapter 2</h2>
 
 <p><strong>Page 32</strong> (while and do Loops): The <code>var
 name</code> example unintentionally exits the loop when the dialog is
-canceled, because browser's have a built-in global
+canceled, because browsers have a built-in global
 variable <code>name</code> whose values are implicitly converted to
 strings.</p>