[css-text-3] More accurate description of Appendix E

Author: fantasai

css-text-3/Overview.bs

@@ -181,7 +181,8 @@ Languages and Typesetting</h3>
     higher quality typography requires authors to communicate to the UA
     the correct linguistic context of the text in the document.
 
-    More information about language tags and their interpretation
+    More information about language tags and their interpretation,
+    particularly the use of script tags for atypical language + writing-system combinations,
     can be found in [[#script-tagging]].
 
 <h3 id="characters">