[css-ruby] Editorial udpates to ruby font size

Author: kojiishi

css-ruby/Overview.src.html

@@ -903,7 +903,8 @@ <h3 id="ruby-size">Ruby Annotation Font Size</h3>
 		However, UA may increase the font size when the it is too small to read,
 		or decrease if the text is too large to avoid ruby annotation being too large.
 		Also, the 'ruby-position: inter-character' usually require different font size such as 25% or 33%.
-	<p>This level of the specification does not provide a mechanism to control the size of <i>ruby annotations</i>.
+	<p>This level of the specification does not provide a mechanism to control the size of <i>ruby annotations</i>
+		relative to <i>ruby base</i>.
 
 <h2 id="ruby-props">
 Ruby Formatting Properties</h2>