[css3-fonts] more tweaks of @font-feature-values wording

Author: John Daggett

css3-fonts/Fonts.html

@@ -4311,11 +4311,15 @@ <h3 id=font-feature-values><span class=secno>6.9 </span>Defining font
    class=prod><dfn id=ltfeature-indexgt><var>&lt;feature-index&gt;</var></dfn>       = an integer value greater than 0 specific to a given font or set of fonts</pre>
 
   <p>These <code>@font-feature-values</code> rules can appear anywhere within
-   a stylesheet and are exposed bidirectionally across @import boundaries. An
-   <code>@font-feature-values</code> rule contains a list of feature value
-   sets, each <dfn id=feature-value-set>feature value set</dfn> containing a
-   series of feature value definitions for a single
-   <code>&lt;feature-type></code>.
+   a stylesheet and are exposed bidirectionally across @import boundaries. A
+   <dfn id=feature-value-set>feature value set</dfn> contains a series of
+   feature value definitions for a single <code>&lt;feature-type></code>. An
+   <code>@font-feature-values</code> rule is composed of a series of these
+   sets. The <code>&lt;feature-type></code> must match, using an ASCII
+   case-insensitive comparison, one of the <em>font specific</em> values of
+   the <a
+   href="#propdef-font-variant-alternates"><code>font-variant-alternates</code></a>
+   property.
 
   <p>If syntax errors occur within the font family list, the entire rule must
    be ignored. When syntax errors occur within a feature value definition,
@@ -4328,7 +4332,7 @@ <h3 id=font-feature-values><span class=secno>6.9 </span>Defining font
   @swash { ornate: 1; }
   annotation { boxed: 4; } /* should be @annotation! */
   @styleset { double-W: 14; sharp-terminals: 16 } /* missing ; */
-  <a href="http://www.angryalien.com/0504/shiningbunnies.html" style="text-decoration: none;">redrum</a>  /* editing mistake */
+  <a href="http://www.angryalien.com/0504/shiningbunnies.html" style="text-decoration: none;">redrum</a>  /* random editing mistake */
 }</pre>
 
   <p>The example above is equivalent to: