Fix typo for region inclusion into cue settings.

webvtt.html

@@ -694,7 +694,7 @@ <h3>Text Track Cues</h3>
   direction</a>, <a title="text track cue snap-to-lines flag">snap-to-lines flag</a>, <a
   title="text track cue line position">line position</a>, <a title="text track cue text
   position">text position</a>, <a title="text track cue size">size</a>, <a title="text
-  track cue alignment">alignment</a>, <a title="text track regon identifier">region</a>,
+  track cue alignment">alignment</a>, <a title="text track regon identifier">region identifier</a>,
   or <a title="text track cue text">text</a> change value, then the user agent must empty
   the <a>text track cue display state</a>, and then immediately run the <a>text track</a>'s
   <a>rules for updating the display of WebVTT text tracks</a>.</p>