Meta: remove an unnecessary id with %

This id was introduced in b29fb58.
It repeats the id of the heading above but with `(` and `)`
percent-escaped. This is not done for any other ids that also contain
those characters.

source

@@ -45254,7 +45254,7 @@ ldh-str       = &lt; as defined in <a href="https://tools.ietf.org/html/rfc1034#
 
   <div w-nodev>
 
-  <p id="date-state-%28type=date%29">When an <code>input</code> element's <code data-x="attr-input-type">type</code> attribute is in
+  <p>When an <code>input</code> element's <code data-x="attr-input-type">type</code> attribute is in
   the <span data-x="attr-input-type-date">Date</span> state, the rules in this section apply.</p>
 
   </div>