[css-writing-modes] Mark at risk: ''sideways-left'' of 'text-orientation'

Author: Koji Ishii

css-writing-modes/Overview.bs

@@ -1244,6 +1244,7 @@ Orienting Text: the 'text-orientation' property</h3>
       <p>Similarly, if an inline child of the box has a 'text-orientation'
       value other than ''sideways-left'', an analogous transformation (and
       bidi isolation) is applied.
+      <p class="note">This value is at-risk and may be dropped during CR.
     <dt><dfn>sideways</dfn></dt>
     <dd><p>This value is equivalent to ''sideways-right'' in ''vertical-rl''
       writing mode and equivalent to ''sideways-left'' in ''vertical-lr''