[css-writing-modes-3] Markup fix

Author: xfq

css-writing-modes-3/Overview.bs

@@ -2034,7 +2034,7 @@ Available Space of Orthogonal Flows</h4>
       <li>the initial containing block’s size
     </ul>
 
-  <p>See [[!CSS3-SIZING]] for further details on CSS sizing terminology and concepts.
+  <p>See [[!css-sizing-3]] for further details on CSS sizing terminology and concepts.
 
 <h4 id="orthogonal-layout">
 Auto-sizing Orthogonal Flow Roots</h4>
@@ -2509,7 +2509,7 @@ Privacy and Security Considerations {#priv-sec}
 
   <ul>
     <li>Added back accidentally-dropped rules for sizing [=orthogonal flows=].
-      Updated wording to use current [[css-sizing-3] terminology.
+      Updated wording to use current [[css-sizing-3]] terminology.
       (<a href="https://github.com/w3c/csswg-drafts/issues/4220">Issue 4220</a>)
   </ul>