[css-writing-modes] fix typo

Author: fantasai

css-writing-modes/Overview.bs

@@ -1233,8 +1233,9 @@ Orienting Text: the 'text-orientation' property</h3>
       <p class="note">This value is at-risk and may be dropped during CR.
       <p class="issue"><a href="https://lists.w3.org/Archives/Public/www-style/2015Apr/0026.html">float interaction when line-left and line-right swap</a>
       <p class="note">If this value is not supported, implementation should drop support for
-        either ''vertical-rl'' or ''sideways'' as well.
-      <p class="issue">Need to mark ''vertical-rl'' at risk
+        either ''vertical-lr'' or ''sideways'' as well,
+        since the combination of the two requires ''sideways-left'' layout.
+      <p class="issue">Need to mark ''vertical-lr'' at risk
     <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''