Editorial: remove user context issue from storage module (#644)

Author: OrKoN

index.bs

@@ -9457,15 +9457,12 @@ partition key attributes=].
     <th>Definition
   <tr>
     <td>"<code>userContext</code>"
-    <td>A user context id
+    <td>A [=user context id=]
   <tr>
     <td>"<code>sourceOrigin"</code>
     <td>The [=serialization of an origin|serialization of the origin=] of resources that can access the storage partition
 </table>
 
-Issue(w3c/webdriver-bidi#570): User contexts are in the process of being
-specified.
-
 [=Remote ends=] may support any number of <dfn>extension storage partition key
 attributes</dfn>. In order to avoid conflicts with other implementations, these
 attributes must begin with a unique identifier for the vendor and user-agent