[css-counter-styles-3] Make the complex counter styles negative-capable.

Author: tabatkins

css-counter-styles-3/Overview.html

@@ -1964,7 +1964,8 @@ <h2 id=complex-predefined-counters><span class=secno>6. </span> Complex
 
   <p> All of the counter styles defined in this section have a <a
    href="#spoken-form"><i title=counter-speak-as>spoken form</i></a> of ‘<a
-   href="#speak-as-numeric"><code class=css>numeric</code></a>’.
+   href="#speak-as-numeric"><code class=css>numeric</code></a>’, and are
+   all <a href="#negative-capable"><i>negative-capable</i></a>.
 
   <h3 id=complex-cjk><span class=secno>6.1. </span> Longhand East Asian
    Counter Styles: ‘<a href="#japanese-informal0"><code

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

@@ -1483,7 +1483,8 @@ <h2 id='complex-predefined-counters'>
 		reusing the algorithm but swapping out some of the other descriptors.
 
 	<p>
-		All of the counter styles defined in this section have a <i title='counter-speak-as'>spoken form</i> of ''numeric''.
+		All of the counter styles defined in this section have a <i title='counter-speak-as'>spoken form</i> of ''numeric'',
+		and are all <i>negative-capable</i>.
 
 
 <h3 id='complex-cjk'>