Simplify pharsing of event firing

As suggested in DOM spec https://dom.spec.whatwg.org/#firing-events-example
this helps with automated extraction of data from specs

Author: dontcallmedom

index.html

@@ -510,13 +510,9 @@ <h2 id="MIDIAccess">
               <li>Let |port:MIDIPort| be the {{MIDIPort}} corresponding to the
               newly-available, or the existing port.
               </li>
-              <li>Let |event:MIDIConnectionEvent| be a newly constructed
-              {{MIDIConnectionEvent}}, with the {{MIDIConnectionEvent/port}}
-              attribute set to the port.
-              </li>
               <li>
                 <a>Fire an event</a> named "statechange" at the {{MIDIAccess}},
-                using the |event| as the event object.
+                using {{MIDIConnectionEvent}} with {{MIDIConnectionEvent/port}} set to |port|.
               </li>
             </ol>
           </dd>
@@ -904,22 +900,16 @@ <h2 id="MIDIPort">
         <ol>
           <li>
             <p>
-              Let <code>port</code> be the {{MIDIPort}}.
-            </p>
-          </li>
-          <li>
-            <p>
-              Let <code>event</code> be a newly constructed
-              {{MIDIConnectionEvent}}, with the <code>port</code> attribute set
-              to the port.
+              Let |port:MIDIPort| be the {{MIDIPort}}.
             </p>
           </li>
           <li>
             <p>
               <a>Fire an event</a> named <a data-lt=
               "MIDIPort.onstatechange">statechange</a> at the {{MIDIPort}}, and
               <a data-lt="MIDIAccess.onstatechange">statechange</a> at the
-              {{MIDIAccess}}, using the <code>event</code> as the event object.
+              {{MIDIAccess}}, using {{MIDIConnectionEvent}}  with the {{MIDIConnectionEvent/port}} attribute set
+              to |port|
             </p>
           </li>
         </ol>
@@ -959,7 +949,7 @@ <h3 id="MIDIInput">
           <ol>
             <li>
               <p>
-                Let <code>port</code> be the {{MIDIInput}}.
+                Let |port:MIDIInput| be the {{MIDIInput}}.
               </p>
             </li>
             <li>
@@ -971,21 +961,14 @@ <h3 id="MIDIInput">
             </li>
             <li>
               <p>
-                Let <code>event</code> be a newly constructed
-                <a>MIDIMessageEvent</a>, with the <code>timestamp</code>
+                <a>Fire an event</a> named "midimessage" at
+                |port|, using {{MIDIMessageEvent}} with the {{Event/timeStamp}}
                 attribute set to the time the message was received by the
-                system, and with the <code>data</code> attribute set to a
-                Uint8Array of MIDI data bytes representing a single MIDI
+                system, and with the {{MIDIMessageEvent/data}} attribute set to a
+                {{Uint8Array}} of MIDI data bytes representing a single MIDI
                 message.
               </p>
             </li>
-            <li>
-              <p>
-                <a>Fire an event</a> named "midimessage" at the
-                <code>port</code>, using the <code>event</code> as the event
-                object.
-              </p>
-            </li>
           </ol>
           <p>
             It is specifically noted that MIDI System Real-Time Messages may