[css-contain-2] rename ContentVisibilityAutoStateChanged to ContentVisibilityAutoStateChange

Per #7603 (comment) the group resolved to use present tense for the event and inteface.
Since then Mozilla and Chrome both implemented the interface under the new name.
https://hg.mozilla.org/mozilla-central/rev/6095dabf5574
https://chromium.googlesource.com/chromium/src/+/9851571ecb54c47a205b2321006577b9799c0ea3

This updates both the event name and interface to reflect the resolution and to match implementation.

Author: myakura

css-contain-2/Overview.bs

@@ -1857,10 +1857,10 @@ Using ''content-visibility: auto''</h3>
 		will be forced to rely on the ''200px'' height estimate.
 	</div>
 
-Detecting ''content-visibility: auto'' state changes: the <a event>contentvisibilityautostatechanged</a> event {#content-visibility-auto-state-changed}
+Detecting ''content-visibility: auto'' state changes: the <a event>contentvisibilityautostatechange</a> event {#content-visibility-auto-state-change}
 --------------------------------------------------------------------------------------------------------------------------------------------
 
-The <dfn event dfn-for="Element">contentvisibilityautostatechanged</dfn> event is fired on an element with ''content-visibility: auto'' style when
+The <dfn event dfn-for="Element">contentvisibilityautostatechange</dfn> event is fired on an element with ''content-visibility: auto'' style when
 the rendering state changes and the element either becomes or stops being
 [=relevant to the user=].
 
@@ -1875,20 +1875,20 @@ This event is dispatched by posting a task at the time when the state change occ
 
 <pre class='idl'>
 [Exposed=Window]
-interface ContentVisibilityAutoStateChangedEvent : Event {
-  constructor(DOMString type, optional ContentVisibilityAutoStateChangedEventInit eventInitDict = {});
+interface ContentVisibilityAutoStateChangeEvent : Event {
+  constructor(DOMString type, optional ContentVisibilityAutoStateChangeEventInit eventInitDict = {});
   readonly attribute boolean skipped;
 };
-dictionary ContentVisibilityAutoStateChangedEventInit : EventInit {
+dictionary ContentVisibilityAutoStateChangeEventInit : EventInit {
   boolean skipped = false;
 };
 </pre>
 
 <div class="attributes">
 
-Description of ContentVisibilityAutoStateChangedEvent attributes:
+Description of ContentVisibilityAutoStateChangeEvent attributes:
 
-: <dfn attribute for=ContentVisibilityAutoStateChangedEvent>skipped</dfn>
+: <dfn attribute for=ContentVisibilityAutoStateChangeEvent>skipped</dfn>
 :: Set to true if target changed state to [=skip its contents=], and false otherwise.
 
 	<wpt>
@@ -1900,10 +1900,10 @@ Description of ContentVisibilityAutoStateChangedEvent attributes:
 
 <div class="members">
 
-Description of ContentVisibilityAutoStateChangedEventInit members:
+Description of ContentVisibilityAutoStateChangeEventInit members:
 
-: <dfn dict-member for=ContentVisibilityAutoStateChangedEventInit>skipped</dfn>
-:: See the description of the {{ContentVisibilityAutoStateChangedEvent/skipped}} attribute.
+: <dfn dict-member for=ContentVisibilityAutoStateChangeEventInit>skipped</dfn>
+:: See the description of the {{ContentVisibilityAutoStateChangeEvent/skipped}} attribute.
 
 </div>
 
@@ -2294,7 +2294,7 @@ Changes from <a href="https://www.w3.org/TR/2020/WD-css-contain-2-20201216/">202
 * Defined that elements having an ancestor with ''content-visibility: hidden'' don't generate boxes in the top layer
 * Defined that being in the top-layer makes an element relevant to the user
 * Noted that paint effects with non-local effects can limit certain optimization opportunities.
-* Add ContentVisibilityAutoStateChanged event
+* Add ContentVisibilityAutoStateChange event
 
 <h3 id="changes-since-2020-06-03">
 Changes from <a href="https://www.w3.org/TR/2020/WD-css-contain-2-20200603/">2020-06-03 Working Draft</a>