Drop BCD table from @scroll-timeline article (#19087)

* Drop BCD table from @scroll-timeline article

This is a follow-up to #19056

w3c/csswg-drafts@fc6766d dropped the
scroll-timeline at-rule from the “Scroll-linked Animations” spec

The feature was only ever implemented in Firefox, and only behind a flag,
and given that it’s been dropped from the spec, it seems very unlikely
to ever be shipped (un-flagged) in Firefox (or in any other browser).

* Update files/en-us/web/css/@scroll-timeline/index.md

Co-authored-by: Jean-Yves Perrier <[email protected]>

* Update files/en-us/web/css/@scroll-timeline/index.md

Co-authored-by: Jean-Yves Perrier <[email protected]>

files/en-us/web/css/@scroll-timeline/index.md

@@ -7,11 +7,11 @@ tags:
   - At-rule
   - CSS
   - Reference
-  - Experimental
+  - Deprecated
 browser-compat: css.at-rules.scroll-timeline
 ---
 
-{{CSSRef}}{{SeeCompatTable}}
+{{CSSRef}}{{Non-standard_header}}{{Deprecated_header}}
 
 The **`@scroll-timeline`** CSS [at-rule](/en-US/docs/Web/CSS/At-rule) defines an [`AnimationTimeline`](/en-US/docs/Web/API/AnimationTimeline) whose time values are determined by scrolling progress within a scroll container and not by minutes or seconds. Once specified, a scroll timeline is associated with a [CSS Animation](/en-US/docs/Web/CSS/CSS_Animations) by using the `animation-timeline` property.
 
@@ -166,9 +166,13 @@ We create an `@scroll-timeline` called `squareTimeline`, setting the `source` as
 
 {{EmbedLiveSample("Simple_example")}}
 
+## Specifications
+
+This feature was in a draft specification and has been removed from it. It is no longer on track to become a standard.
+
 ## Browser compatibility
 
-{{Compat}}
+No released browser ever implemented this feature.
 
 ## See also