Update to ECMAscript 2023 / 14.0 (#329)

Adjustments as a result of the update:
- 2 exceptions removed:
  - look-behind assertions
  - Class static initialization blocks

index.html

@@ -194,14 +194,12 @@ <h3>Core web specifications</h3>
         <p>Devices MUST be conforming implementations of the following specifications:</p>
         <ul>
           <li>DOM [[!DOM]]</li>
-          <li>ECMAScript 2022 Language Specification [[!ECMASCRIPT-2022]]
+          <li>ECMAScript 2023 Language Specification [[!ECMASCRIPT-2023]]
             <ul>
               <li>Exceptions:
                 <ul>
-                  <li><a href="https://262.ecma-international.org/13.0/#prod-Assertion">look-behind assertions</a> are not yet widely supported.</li>
-                  <li>The <a href="https://262.ecma-international.org/13.0/#sec-function.prototype.tostring"><code>Function.prototype.toString</code> revisions from ECMAScript 2019</a> are not yet widely supported.</li>
-                  <li><a href="https://262.ecma-international.org/13.0/#sec-classstaticblockdefinition-record-specification-type">Class static initialization blocks</a> are not yet widely supported.</li>
-                  <li><a href="https://262.ecma-international.org/13.0/#sec-get-regexp.prototype.hasIndices">RegExp Match Indices (hasIndices <code>/d</code> flag)</a> is not yet widely supported.</li>
+                  <li>The <a href="https://262.ecma-international.org/14.0/#sec-function.prototype.tostring"><code>Function.prototype.toString</code> revisions from ECMAScript 2019</a> are not yet widely supported.</li>
+                  <li><a href="https://262.ecma-international.org/14.0/#sec-get-regexp.prototype.hasIndices">RegExp Match Indices (hasIndices <code>/d</code> flag)</a> is not yet widely supported.</li>
                </ul>
             </ul>
           </li>