[css-contain] Move info on content-visibility animations from L3 to L2

See #8627

css-contain-2/Overview.bs

@@ -1618,7 +1618,7 @@ Suppressing An Element's Contents Entirely: the 'content-visibility' property {#
  Initial: visible
  Inherited: no
  Applies to: elements for which [=size containment=] can apply
- Animation type: not animatable
+ Animation type: see [[#content-visibility-animation]]
  </pre>
 
  <wpt>
@@ -2040,6 +2040,18 @@ Suppressing An Element's Contents Entirely: the 'content-visibility' property {#
 
  </div>
 
+<h3 id='content-visibility-animation'>
+Animating and Interpolating 'content-visibility'</h3>
+
+ In general,
+ the 'content-visibility' property’s [=animation type=] is [=discrete=].
+ However,
+ similar to interpolation of 'visibility'
+ (see [[web-animations-1#animating-visibility]]),
+ during interpolation between ''content-visibility/hidden''
+ and any other 'content-visibility' value,
+ <var ignore>p</var> values between 0 and 1
+ map to the non-''content-visibility/hidden'' value.
 
 <h3 id='using-cv-hidden'>
 Using ''content-visibility: hidden''</h3>
@@ -2646,6 +2658,8 @@ Changes from <a href="https://www.w3.org/TR/2022/WD-css-contain-2-20220917/">202
 * Move the definition of inline-size containement from the Level 3 specification
  to this Level 2.
  (<a href="https://github.com/w3c/csswg-drafts/issues/10433">Issue 10433</a>)
+* Make the 'content-visibility' property animatable.
+ (<a href="https://github.com/w3c/csswg-drafts/issues/8627">Issue 8627</a>)
 
 <h3 id="changes-since-2020-12-16">
 Changes from <a href="https://www.w3.org/TR/2020/WD-css-contain-2-20201216/">2020-12-16 Working Draft</a>

css-contain-3/Overview.bs

@@ -946,30 +946,8 @@ The <code>CSSContainerRule</code> interface</h3>
 Suppressing An Element’s Contents Entirely: the 'content-visibility' property {#content-visibility}
 =================
 
- <pre class=propdef>
- Name: content-visibility
- Value: visible | auto | hidden
- Initial: visible
- Inherited: no
- Applies to: elements for which [=size containment=] can apply
- Animation type: see [[#content-visibility-animation]]
- </pre>
-
  Issue: [[css-contain-2#content-visibility]]
 
-<h3 id='content-visibility-animation'>
-Animating and Interpolating 'content-visibility'</h3>
-
- In general,
- the 'content-visibility' property’s [=animation type=] is [=discrete=].
- However,
- similar to interpolation of 'visibility'
- (see [[web-animations-1#animating-visibility]]),
- during interpolation between ''content-visibility/hidden''
- and any other 'content-visibility' value,
- <var>p</var> values between 0 and 1
- map to the non-''content-visibility/hidden'' value.
-
 Privacy Considerations {#privacy}
 =================================
 
@@ -1007,8 +985,6 @@ Changes since the 18 August 2022 Working Draft</h3>
  * Correct typo in 'container-type' syntax, to clarify that ''normal'' cannot
  be combined with other values.
  (<a href="https://github.com/w3c/csswg-drafts/issues/7669">Issue 7669</a>)
- * Make the 'content-visibility' property animatable.
- (<a href="https://github.com/w3c/csswg-drafts/issues/8627">Issue 8627</a>)
  * Allow ''var()'' references in [=container size queries=].
  (<a href="https://github.com/w3c/csswg-drafts/issues/8088">Issue 8088</a>)
  * Allow comma-separated <<container-condition>>s to match different containers.