[css-lists-3] Split sentence.

Author: fantasai

css-lists-3/Overview.bs

@@ -910,12 +910,12 @@ Creating and Inheriting Counters</h3>
 	or through instantiation on the element directly.
 	These counters are represented as a <dfn>CSS counters set</dfn>,
 	which is a [=/set=]
-	whose values are [=tuples=] of:
+	whose values are each a [=tuple=] of:
 	a [=string=] (representing a counter’s name),
 	an element (representing the counter’s originating element),
-	and an integer (representing the counter’s value),
-	the latest one of a given name
-	representing the “innermost” counter of that name.
+	and an integer (representing the counter’s value).
+	The latest [=counter=] of a given name in that set
+	represents the “innermost” counter of that name.
 
 	<div algorithm>
 		An element [=inherit counters|inherits=] its initial set of counters