Add issue about & requiring either escaping or CDATA in XML.

Author: tabatkins

css3-hierarchies/Overview.html

@@ -281,6 +281,11 @@ <h2 id=nesting-selector><span class=secno>2. </span> The &amp; Selector</h2>
    nesting selector. The nesting selector represents the elements matched by
    the parent rule set's selector list.
 
+  <p class=issue>Introducing the &lsquo;<code class=css>&amp;</code>&rsquo;
+   character will cause issues with CSS embedded directly in XML, as it's the
+   first character used in CSS syntax that either requires escaping or using
+   CDATA. Do we need to change this?
+
   <div class=example>
    <p>The following example using Hierarchies:
 

css3-hierarchies/Overview.src.html

@@ -162,7 +162,9 @@ <h2 id="nesting-selector">
 
 	<p>This specification provides a mechanism that allows for the nesting of style rules within other style rules. A nested style rule can used anywhere that a declaration can be used.</p>
 
-	<p>In order to accomplish nesting, this specification defines a new simple selector called the nesting selector, represented in selectors by the '&amp;' character. All complex selectors in the selector lists of nested rule sets must start with the nesting selector. The nesting selector represents the elements matched by the parent rule set's selector list.
+	<p>In order to accomplish nesting, this specification defines a new simple selector called the nesting selector, represented in selectors by the '&amp;' character. All complex selectors in the selector lists of nested rule sets must start with the nesting selector. The nesting selector represents the elements matched by the parent rule set's selector list.</p>
+
+	<p class='issue'>Introducing the ''&amp;'' character will cause issues with CSS embedded directly in XML, as it's the first character used in CSS syntax that either requires escaping or using CDATA.  Do we need to change this?</p>
 
 	<div class='example'>
 		<p>The following example using Hierarchies: