Revert "[css-lists-3] Move "UAs can do whatever w/ list-item" text further up." because it made significant changes to normative requirements and we're still discussing how that should work.

This reverts commit c505749.

Author: fantasai

css-lists-3/Overview.bs

@@ -1073,29 +1073,13 @@ The Implicit ''list-item'' Counter</h3>
 	Specifically,
 	unless the 'counter-increment' property explicitly specifies
 	a different increment for the ''list-item'' counter,
-	it must be incremented by the <dfn export>default list-item increment</dfn>
-	(which is 1 by default)
-	on every [=list item=],
+	it must be incremented by 1 on every [=list item=],
 	at the same time that <a>counters</a> are normally incremented
 	(exactly as if the [=list item=] had ''list-item 1'' appended to their 'counter-increment' value,
 	including side-effects such as possibly [=instantiating=] a new [=counter=], etc).
 	This does not affect the [=specified value|specified=] or [=computed values=]
 	of 'counter-increment'.
 
-	The host language's semantics can imply different values
-	for this automatic counter-increment.
-	In that case, the [=default list-item increment=] must instead 
-	reflect the host language's semantics.
-	(For example, in HTML <code highlight=html>&lt;ol reversed></code>
-	implies that ''list-item'' counts <em>down</em> on that list,
-	so the [=default list-item increment=] is -1 for <{li}>s in such lists.
-	See, e.g. [[#ua-stylsheet]].
-
-	<!--
-	See old <a href="https://github.com/w3c/csswg-drafts/issues/2464#issuecomment-375492907">WG discussions</a>
-	and newer <a href="https://github.com/w3c/csswg-drafts/issues/3686">issue discussion</a>.
-	-->
-
 	<div class="example">
 		Because each [=list item=] automatically increments
 		the ''counter-increment/list-item'' counter by 1,
@@ -1144,6 +1128,19 @@ The Implicit ''list-item'' Counter</h3>
 		</pre>
 	</div>
 
+	UAs and host languages should ensure
+	that the ''counter-increment/list-item'' counter values
+	by default
+	reflect the underlying numeric value dictated by host language semantics
+	when setting up list item styling
+	in their UA style sheet and presentational hint style mappings.
+	See, e.g. [[#ua-stylesheet]].
+
+	<!--
+	See old <a href="https://github.com/w3c/csswg-drafts/issues/2464#issuecomment-375492907">WG discussions</a>
+	and newer <a href="https://github.com/w3c/csswg-drafts/issues/3686">issue discussion</a>.
+	-->
+
 	<div class="example">
 		In the following example,
 		the 'content' property is used to create tiered numbering