[css-syntax] Return U+FFFD for escaped surrogate code points.

Author: SimonSapin

css-syntax/Overview.html

@@ -12,7 +12,7 @@
 </a></p>
   <h1 class="p-name no-ref" id=title>CSS Syntax Module Level 3</h1>
   <h2 class="no-num no-toc no-ref" id=subtitle><span class=content>Editor's Draft,
-    <span class=dt-updated><span class=value-title title=20130809>9 August 2013</span></span></span></h2>
+    <span class=dt-updated><span class=value-title title=20130812>12 August 2013</span></span></span></h2>
   <div data-fill-with=spec-metadata><dl><dt>This version:<dd><a class=u-url href=http://dev.w3.org/csswg/css-syntax>http://dev.w3.org/csswg/css-syntax</a><dt>Editor's Draft:<dd><a href=http://dev.w3.org/csswg/css-syntax>http://dev.w3.org/csswg/css-syntax</a>
 <dt>Feedback:</dt>
     <dd><a href="mailto:www-style@w3.org?subject=%5Bcss-syntax%5D%20feedback">www-style@w3.org</a>
@@ -1306,10 +1306,15 @@ <h4 data-level=4.3.7 id=consume-an-escaped-character><span class=secno>4.3.7 </s
 			consume it as well.
 			Interpret the <a href=#hex-digit>hex digits</a> as a hexadecimal number.
 			If this number is zero,
+			or is between U+D800 and U+DFFF included,
 			or is greater than the <a href=#maximum-allowed-codepoint>maximum allowed codepoint</a>,
 			return U+FFFD REPLACEMENT CHARACTER (�).
 			Otherwise, return the character with that codepoint.
 
+			<p class=note>
+				U+D800 to U+DFFF are the
+				<a href=http://www.unicode.org/glossary/#surrogate_code_point>surrogate code points</a>.
+
 		<dt>EOF character
 		<dd>
 			Return U+FFFD REPLACEMENT CHARACTER (�).

css-syntax/Overview.src.html

@@ -1189,10 +1189,15 @@ <h4>
 			consume it as well.
 			Interpret the <a>hex digits</a> as a hexadecimal number.
 			If this number is zero,
+			or is between U+D800 and U+DFFF included,
 			or is greater than the <a>maximum allowed codepoint</a>,
 			return U+FFFD REPLACEMENT CHARACTER (�).
 			Otherwise, return the character with that codepoint.
 
+			<p class=note>
+				U+D800 to U+DFFF are the
+				<a href="http://www.unicode.org/glossary/#surrogate_code_point">surrogate code points</a>.
+
 		<dt>EOF character
 		<dd>
 			Return U+FFFD REPLACEMENT CHARACTER (�).