[css-writing-modes] Improve export of physical directions.

Author: fantasai

css-writing-modes-3/Overview.bs

@@ -1465,8 +1465,11 @@ Abstract Box Terminology</h2>
   <dl export>
   <dt><dfn>physical</dfn>
     <dd>Interpreted relative to the page, independent of writing mode.
-    The <dfn lt="physical direction">physical directions</dfn> are <dfn>left</dfn>, <dfn>right</dfn>, <dfn>top</dfn>, and
-    <dfn>bottom</dfn>.
+    The <dfn lt="physical direction">physical directions</dfn> are
+    <dfn lt="physical left | left">left</dfn>,
+    <dfn lt="physical right | right">right</dfn>,
+    <dfn lt="physical top | top">top</dfn>, and
+    <dfn lt="physical bottom | bottom">bottom</dfn>.
   <dt><dfn><a href="#logical-directions">flow-relative</a></dfn>
     <dd>Interpreted relative to the flow of content.
     The flow-relative directions are <i>start</i> and <i>end</i>,

css-writing-modes/Overview.bs

@@ -1475,8 +1475,11 @@ Abstract Box Terminology</h2>
   <dl export>
   <dt><dfn>physical</dfn>
     <dd>Interpreted relative to the page, independent of writing mode.
-    The <dfn lt="physical direction">physical directions</dfn> are <dfn>left</dfn>, <dfn>right</dfn>, <dfn>top</dfn>, and
-    <dfn>bottom</dfn>.
+    The <dfn lt="physical direction">physical directions</dfn> are
+    <dfn lt="physical left | left">left</dfn>,
+    <dfn lt="physical right | right">right</dfn>,
+    <dfn lt="physical top | top">top</dfn>, and
+    <dfn lt="physical bottom | bottom">bottom</dfn>.
   <dt><dfn><a href="#logical-directions">flow-relative</a></dfn>
     <dd>Interpreted relative to the flow of content.
     The flow-relative directions are <i>start</i> and <i>end</i>,