[css-ruby] Clarify that HTML's rbc is an anonymous box

Author: fantasai

css-ruby/Overview.html

@@ -21,7 +21,7 @@
 
   <meta content="CSS Ruby Module Level 1" name=dcterms.title>
   <meta content=text name=dcterms.type>
-  <meta content=2014-03-20 name=dcterms.date>
+  <meta content=2014-05-09 name=dcterms.date>
   <meta content="Elika J. Etemad" name=dcterms.creator>
   <meta content="Koji Ishii" name=dcterms.creator>
   <meta content="Richard Ishida" name=dcterms.creator>
@@ -42,8 +42,8 @@
    <h1 class=p-name>CSS Ruby Module Level 1</h1>
 
    <h2 class="no-num no-toc">Editor's Draft <time class=dt-updated
-    datetime=20140320>20 March 2014</time>
-    <!-- for HTML4 doctype: <span class="value-title" title="20140320">20 March 2014</span></span> --></h2>
+    datetime=20140509> 9 May 2014</time>
+    <!-- for HTML4 doctype: <span class="value-title" title="20140509"> 9 May 2014</span></span> --></h2>
 
    <dl>
     <dt>This version:
@@ -516,7 +516,7 @@ <h3 id=ruby-display><span class=secno>2.1. </span> Ruby-specific ‘<code
    <dd>Specifies that an element generates a <dfn id=ruby-base-container-box
     title="ruby base container box | ruby base container">ruby base container
     box</dfn>. (Corresponds to XHTML <code>&lt;rbc&gt;</code> elements;
-    always implied in HTML.)
+    generated as an anonymous box in HTML.)
 
    <dt>‘<code class=css>ruby-text-container</code>’
 

css-ruby/Overview.src.html

@@ -259,7 +259,7 @@ <h3 id="ruby-display">
 			(Corresponds to HTML/XHTML <code>&lt;rt&gt;</code> elements.)
 		<dt>''ruby-base-container''
 			<dd>Specifies that an element generates a <dfn title="ruby base container box | ruby base container">ruby base container box</dfn>.
-			(Corresponds to XHTML <code>&lt;rbc&gt;</code> elements; always implied in HTML.)
+			(Corresponds to XHTML <code>&lt;rbc&gt;</code> elements; generated as an anonymous box in HTML.)
 		<dt>''ruby-text-container''
 			<dd>Specifies that an element generates a <dfn title="ruby annotation container box | ruby annotation container">ruby annotation container box</dfn>.
 			(Corresponds to HTML/XHTML <code>&lt;rtc&gt;</code> elements.)