[css-syntax] Add some examples for <An+B>

Author: SimonSapin

css-syntax/Overview.bs

@@ -2607,7 +2607,10 @@ The <var>An+B</var> microsyntax</h2>
 
 	<div class="example">
 		<p>Example:
-		<pre>-n+6   /* represents the first 6 elements of the list */</pre>
+		<pre><!--
+			-->-1n+6   /* represents the first 6 elements of the list */&#xa;<!--
+			-->-4n+10  /* represents the 2nd, 6th, and 10th elements of the list */
+		</pre>
 	</div>
 
 	If both <var>A</var> and <var>B</var> are 0,
@@ -2674,6 +2677,15 @@ Informal Syntax Description</h3>
 		-->+ 2</pre>
 	</div>
 
+	When B is negative, its minus sign replaces the ''+'' sign.
+
+	<div class="example">
+		<p>Valid example:
+		<pre>3n-6</pre>
+		<p>Invalid example:
+		<pre>3n + -6</pre>
+	</div>
+
 
 <h3 id="the-anb-type">
 The <code>&lt;an+b></code> type</h3>

css-syntax/Overview.html

@@ -58,7 +58,7 @@
 </p>
   <h1 class="p-name no-ref" id=title>CSS Syntax Module Level 3</h1>
   <h2 class="no-num no-toc no-ref heading settled heading" id=subtitle><span class=content>Editor’s Draft,
-    <span class=dt-updated><span class=value-title title=20140221>21 February 2014</span></span></span></h2>
+    <span class=dt-updated><span class=value-title title=20140301>1 March 2014</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>Latest version:<dd><a href=http://www.w3.org/TR/css-syntax-3/>http://www.w3.org/TR/css-syntax-3/</a><dt>Editor’s Draft:<dd><a href=http://dev.w3.org/csswg/css-syntax/>http://dev.w3.org/csswg/css-syntax/</a><dt>Previous Versions:<dd><a href=http://www.w3.org/TR/2013/WD-css-syntax-3-20131105/ rel=previous>http://www.w3.org/TR/2013/WD-css-syntax-3-20131105/</a><dd><a href=http://www.w3.org/TR/2013/WD-css-syntax-3-20130919/ rel=previous>http://www.w3.org/TR/2013/WD-css-syntax-3-20130919/</a>
     <dt>Feedback:</dt>
         <dd><a href="mailto:www-style@w3.org?subject=%5Bcss-syntax%5D%20feedback">www-style@w3.org</a>
@@ -4118,7 +4118,9 @@ <h2 class="heading settled heading" data-level=6 id=anb><span class=secno>6 </sp
 
 	<div class=example>
 		<p>Example:
-<pre>-n+6   /* represents the first 6 elements of the list */</pre>	</div>
+		<pre>-1n+6   /* represents the first 6 elements of the list */
+-4n+10  /* represents the 2nd, 6th, and 10th elements of the list */
+</pre>	</div>
 
 <p>	If both <var>A</var> and <var>B</var> are 0,
 	the pseudo-class represents no element in the list.
@@ -4174,6 +4176,13 @@ <h3 class="heading settled heading" data-level=6.1 id=anb-syntax><span class=sec
 + 2n
 + 2</pre>	</div>
 
+<p>	When B is negative, its minus sign replaces the <span class=css data-link-type=maybe title=+>+</span> sign.
+
+	<div class=example>
+		<p>Valid example:
+<pre>3n-6</pre>		<p>Invalid example:
+<pre>3n + -6</pre>	</div>
+
 
 <h3 class="heading settled heading" data-level=6.2 id=the-anb-type><span class=secno>6.2 </span><span class=content>
 The <code>&lt;an+b&gt;</code> type</span><a class=self-link href=#the-anb-type></a></h3>