[e] (0) Clarify how bidi paragraph separation works

Fixing https://www.w3.org/Bugs/Public/show_bug.cgi?id=17065
Affected topics: Video Text Tracks

git-svn-id: http://svn.whatwg.org/webapps@7428 340c8d12-0b0e-0410-8428-c7bf67bfef74

source

@@ -114024,6 +114024,10 @@ iframe[seamless] { display: block; }
       to determine the <i>paragraph embedding level</i> of the first
       Unicode paragraph of the cue. <a href="#refsBIDI">[BIDI]</a></p>
 
+      <p class="note">Within a cue, paragraph boundaries are only denoted by Type B characters, such
+      as U+000A LINE FEED (LF), U+0085 NEXT LINE (NEL), and U+2029 PARAGRAPH SEPARATOR. (This means
+      each line of the cue is reordered as if it was a separate paragraph.)</p>
+
      </li>
 
      <li>