[css-counter-styles] Add a note about the additive algorithm not always finding possible representations.

Author: tabatkins

css-counter-styles/Overview.html

@@ -638,6 +638,17 @@ <h4 id="additive-system" data-level="3.1.6"><span class="secno">3.1.6 </span>
 	User agents must support representations at least 20 characters long, 
 	but they may choose to instead use the fallback style for representations that would be longer than 20 characters.
 
+</p><p class="note">	Note: All of the predefined additive <a data-autolink="maybe" class="css" href="#at-counter-style">@counter-style</a> rules in this specification 
+	produce representations for every value in their range,
+	but it's possible to produce values for <a data-autolink="maybe" class="css" href="#additive-symbols">additive-symbols</a> that will fail to find a representation
+	with the algorithm defined above,
+	even though theoretically a representation could be found.
+	For example, if a <a data-autolink="maybe" class="css" href="#at-counter-style">@counter-style</a> was defined with <span data-autolink="maybe" class="css">additive-symbols: 3 "a", 2 "b";</span>,
+	the algorithm defined above will fail to find a representation for a counter value of 4,
+	even though theoretically a "bb" representation would work.
+	While unfortunate, this is required to maintain the property that the algorithm runs in linear time
+	relative to the size of the counter value.
+
 
 </p><h4 id="override-system" data-level="3.1.7"><span class="secno">3.1.7 </span>
 Tweaking Existing Counter Styles: the <a data-autolink="maybe" class="css" href="#override">override</a> system</h4>
@@ -1688,7 +1699,7 @@ <h5 class="no-num no-toc" id="limited-chinese">
 		counter value.
 	</li></ol>
 
-<p>	For all of these counter styles, the <a data-autolink="property" class="property" title="suffix" href="#suffix">suffix</a>is "&#12289;" U+3001, 
+<p>	For all of these counter styles, the <a data-autolink="property" class="property" title="suffix" href="#suffix">suffix</a> is "&#12289;" U+3001, 
 	the <a data-autolink="property" class="property" title="fallback" href="#fallback">fallback</a> is <a data-autolink="maybe" class="css" href="#cjk-decimal">cjk-decimal</a>, 
 	the <a data-autolink="property" class="property" title="range" href="#range">range</a> is <span data-autolink="maybe" class="css">-9999 9999</span>,
 	and the <a data-autolink="property" class="property" title="negative" href="#negative">negative</a> value is given in the table of symbols for each style.
@@ -2459,6 +2470,7 @@ <h2 id="acknowledgments" class="no-num">
 	     http://people.netscape.com/smontagu/writings/HebrewNumbers.html
 	     http://www.ethiopic.org/Collation/OrderedLists.html
 	     http://bugzilla.mozilla.org/show_bug.cgi?id=102252 -->
+
 </p><h2 class="no-ref no-num" id="conformance">
 Conformance</h2>
 

css-counter-styles/Overview.src.html

@@ -564,6 +564,17 @@ <h4 id="additive-system">
 	User agents must support representations at least 20 characters long, 
 	but they may choose to instead use the fallback style for representations that would be longer than 20 characters.
 
+	Note: All of the predefined additive ''@counter-style'' rules in this specification 
+	produce representations for every value in their range,
+	but it's possible to produce values for ''additive-symbols'' that will fail to find a representation
+	with the algorithm defined above,
+	even though theoretically a representation could be found.
+	For example, if a ''@counter-style'' was defined with ''additive-symbols: 3 "a", 2 "b";'',
+	the algorithm defined above will fail to find a representation for a counter value of 4,
+	even though theoretically a "bb" representation would work.
+	While unfortunate, this is required to maintain the property that the algorithm runs in linear time
+	relative to the size of the counter value.
+
 
 <h4 id="override-system">
 Tweaking Existing Counter Styles: the ''override'' system</h4>