Drop exception comment in the defintion of HAVE_METADATA

Found by Jean-Yves Avenard:
#286 (comment)

source

@@ -31245,9 +31245,9 @@ interface <dfn>HTMLMediaElement</dfn> : <span>HTMLElement</span> {
    <dt><dfn><code data-x="dom-media-HAVE_METADATA">HAVE_METADATA</code></dfn> (numeric value 1)</dt>
 
    <dd><p>Enough of the resource has been obtained that the duration of the resource is available.
-   In the case of a <code>video</code> element, the dimensions of the video are also available. The
-   API will no longer throw an exception when seeking. No <span>media data</span> is available for
-   the immediate <span>current playback position</span>.</p></dd>
+   In the case of a <code>video</code> element, the dimensions of the video are also available. No
+   <span>media data</span> is available for the immediate <span>current playback
+   position</span>.</p></dd>
 
    <dt><dfn><code data-x="dom-media-HAVE_CURRENT_DATA">HAVE_CURRENT_DATA</code></dfn> (numeric value 2)</dt>
 
@@ -118275,6 +118275,7 @@ INSERT INTERFACES HERE
   Jasper Bryant-Greene,
   Jasper St. Pierre,
   Jatinder Mann,
+  Jean-Yves Avenard,
   Jed Hartman,
   Jeff Balogh,
   Jeff Cutsinger,