Add "Name from Content" accname step for ::marker pseudo-element (#2419)

Co-authored-by: Rahim Abdi <[email protected]>
Co-authored-by: James Nurthen <[email protected]>

Author: 3 people

accname/index.html

@@ -665,8 +665,13 @@ <h4>Computation steps</h4>
                       <span id="step2F.ii"><!-- Don't link to this legacy numbered ID. --></span><em>Name From Generated Content:</em> Check for
                       <abbr title="Cascading Style Sheets">CSS</abbr> generated textual content associated with the <code>current node</code> and include it in the <code>accumulated text</code>. The
                       <abbr title="Cascading Style Sheets">CSS</abbr> <a href="https://www.w3.org/TR/selectors-3/#gen-content"><code>::before</code> and <code>::after</code></a> pseudo elements
-                      [[!CSS2]] can provide textual content for [=element|elements=] that have a content model.
+                      [[!CSS2]] can provide textual content for [=element|elements=] that have a content model, in addition to the
+                      <a href="https://www.w3.org/TR/css-pseudo-4/#selectordef-marker"><code>::marker</code></a> pseudo element.
                       <ol class="acc-ol">
+                        <li id="comp_name_from_content_pseudo_element_marker">
+                          For <code>::marker</code> pseudo elements, <a class="termref">User agents</a> MUST append <abbr title="Cascading Style Sheets">CSS</abbr> textual content, without a space, to
+                          the textual content of the <code>current node</code> if the <code>current node</code> supports <code>::marker</code>.
+                        </li>
                         <li id="comp_name_from_content_pseudo_element_before">
                           For <code>::before</code> pseudo elements, <a class="termref">User agents</a> MUST prepend <abbr title="Cascading Style Sheets">CSS</abbr> textual content, without a space,
                           to the textual content of the <code>current node</code>.