[css-counter-styles-3] Add a note to 'symbols' about the syntax of idents.

Author: tabatkins

css-counter-styles-3/Overview.html

@@ -1351,6 +1351,15 @@ <h3 id=counter-style-symbols><span class=secno>3.7. </span> Marker
    object size</a> of an image <a href="#counter-symbol"><i>counter
    symbol</i></a> is a 1em by 1em square.
 
+  <p class=note> If using identifiers rather than strings to define the
+   symbols, be aware of the syntax of identifiers. In particular, ascii
+   non-letters like "*" are not identifiers, and so must be quoted in a
+   string. Hex escapes, used in several of the counter styles defined in this
+   specification, "eat" the following space (to allow a digit to follow a hex
+   escape without ambiguity), so two spaces must be put after a hex escape to
+   separate it from the following one, or else they'll be considered
+   adjacent, and part of the same identifier.
+
   <h3 id=counter-style-speak-as><span class=secno>3.8. </span> Speech
    Synthesis: the ‘<a href="#descdef-speak-as"><code
    class=property>speak-as</code></a>’ descriptor</h3>

css-counter-styles-3/Overview.src.html

@@ -921,6 +921,20 @@ <h3 id='counter-style-symbols'>
 		Images are rendered as inline replaced elements.  
 		The <a href="http://dev.w3.org/csswg/css3-images/#default-object-size">default object size</a> of an image <i>counter symbol</i> is a 1em by 1em square.
 
+	<p class='note'>
+		If using identifiers rather than strings to define the symbols,
+		be aware of the syntax of identifiers.
+		In particular, ascii non-letters like "*" are not identifiers,
+		and so must be quoted in a string.
+		Hex escapes, 
+		used in several of the counter styles defined in this specification,
+		"eat" the following space
+		(to allow a digit to follow a hex escape without ambiguity),
+		so two spaces must be put after a hex escape
+		to separate it from the following one,
+		or else they'll be considered adjacent,
+		and part of the same identifier.
+
 
 <h3 id='counter-style-speak-as'>
 Speech Synthesis: the 'speak-as' descriptor</h3>