Update documentation.html

Mentions that the I-D number has been reset to avoid confusion.

Author: Relequestual

documentation.html

@@ -5,6 +5,7 @@
 <h2>Specification</h2>
 <div class="block">
     <p>The latest Internet-Draft at the IETF is v5, published 2016-10-13.
+    (Due to a change in authorship the I-D numbering has been reset).
     The specification is split into three parts, Core, Validation, and Hyper-Schema:</p>
     <table class="key-value">
         <tr>