[selectors] Remove issue on ID selector syntax; closed no change per WG resolution

Author: fantasai

selectors/Overview.src.html

@@ -1583,11 +1583,6 @@ <h3 id="id-selectors">
     An ID selector represents an element instance that has an identifier that matches the identifier in the ID selector.
     (It is possible in non-conforming documents for multiple elements to match a single ID selector.)
 
-  <p class='issue'>
-    In Quirks Mode, we accept all hash tokens, not just ones whose value matches the ident syntax.
-    Should we change the Standards Mode to do that, too?
-    Note that HTML5 loosened the definition of valid ids to allow things starting with numbers, etc.
-
   <div class="example">
     <p>Examples:
     <p>The following ID selector represents an <code>h1</code> element