chore: add ISO/IEC 646:1991 to informative references

Signed-off-by: Wouter Termont <[email protected]>

Author: woutermont

protocol.html

@@ -1544,6 +1544,8 @@ <h3 property="schema:name">Normative References</h3>
                 <h3 property="schema:name">Informative References</h3>
                 <div datatype="rdf:HTML" property="schema:description">
                   <dl class="bibliography" resource="">
+                    <dt id="bib-ascii">[ASCII]</dt>
+                    <dd><a href="https://www.iso.org/standard/4777.html" rel="cito:citesAsPotentialSolution"><cite>Information technology — ISO 7-bit coded character set for information interchange</cite></a>. ISO/IEC. December 1991. Published. URL: <a href="https://www.iso.org/standard/4777.html">https://www.iso.org/standard/4777.html</a></dd>
                     <dt id="bib-atag20">[ATAG20]</dt>
                     <dd><a href="https://www.w3.org/TR/ATAG20/" rel="cito:citesAsPotentialSolution"><cite>Authoring Tool Accessibility Guidelines (ATAG) 2.0</cite></a>. Jan Richards; Jeanne F Spellman; Jutta Treviranus.  W3C. 24 September 2015. W3C Recommendation. URL: <a href="https://www.w3.org/TR/ATAG20/">https://www.w3.org/TR/ATAG20/</a></dd>
                     <dt id="bib-coga-usable">[COGA-USABLE]</dt>