tweak wording on Tibetan example

Author: fantasai

css3-writing-modes/Overview.html

@@ -3424,7 +3424,8 @@ <h2 class=no-num id=character-properties>Appendix A. Characters and
    tailor this definition as appropriate to match typographic convention. For
    example, when typesetting &lsquo;<a href="#upright"><code
    class=css>upright</code></a>&rsquo;, Tibetan tsek and shad marks are kept
-   with the preceding letters, rather than standing alone.
+   with the preceding letters, rather than treated as an independent cluster.
+   
 
   <p>Unicode defines properties for characters, but for &lsquo;<a
    href="#text-orientation0"><code

css3-writing-modes/Overview.src.html

@@ -2575,7 +2575,7 @@ <h2 id="character-properties" class="no-num">Appendix A.
     The UA may further tailor this definition as appropriate to match
     typographic convention. For example, when typesetting ''upright'',
     Tibetan tsek and shad marks are kept with the preceding letters,
-    rather than standing alone.
+    rather than treated as an independent cluster.
 
   <p>Unicode defines properties for characters, but for 'text-orientation' and
     <a href="#vertical-typesetting-details">Vertical Typesetting Synthesis</a>,