[css-text] Clarify incorporation of 'letter-spacing' and 'word-spacing' into tab-size. #643

Author: fantasai

css-text/Overview.bs

@@ -728,7 +728,7 @@ Languages and Typesetting</h4>
 
     <p>This property determines the tab size used to render preserved tab characters (U+0009).
       A <<number>> represents the measure as a multiple of the space character's advance width (U+0020)
-      plus the associated 'letter-spacing' and 'word-spacing'.
+      including its associated 'letter-spacing' and 'word-spacing'.
       Negative values are not allowed.
 
 <h2 id="line-breaking">