[giow] (1) Make the text/vtt registration mention the magic signature…

… for empty WebVTT files (not that that's particularly useful to detect, but at least it makes the parser and registration consistent).

Affected topics: Video Text Tracks

git-svn-id: http://svn.whatwg.org/webapps@6997 340c8d12-0b0e-0410-8428-c7bf67bfef74

source

@@ -110415,18 +110415,20 @@ if (s = prompt('What is your name?')) {
     <dl>
      <dt>Magic number(s):</dt>
      <dd>
-      <p>WebVTT files all begin with one of the following byte sequences:</p>
+      <p>WebVTT files all begin with one of the following byte sequences (where "EOF" means the end of the file):</p>
       <ul class="brief">
        <li> EF BB BF 57 45 42 56 54 54 0A
        <li> EF BB BF 57 45 42 56 54 54 0D
        <li> EF BB BF 57 45 42 56 54 54 20
        <li> EF BB BF 57 45 42 56 54 54 09
+       <li> EF BB BF 57 45 42 56 54 54 EOF
        <li>          57 45 42 56 54 54 0A
        <li>          57 45 42 56 54 54 0D
        <li>          57 45 42 56 54 54 20
        <li>          57 45 42 56 54 54 09
+       <li>          57 45 42 56 54 54 EOF
       </ul>
-      <p class="note">(An optional UTF-8 BOM, the ASCII string "<code title="">WEBVTT</code>", and finally a space, tab, or line break.)
+      <p class="note">(An optional UTF-8 BOM, the ASCII string "<code title="">WEBVTT</code>", and finally a space, tab, line break, or the end of the file.)
      </dd>
      <dt>File extension(s):</dt>
      <dd>"<code title="">vtt</code>"</dd>