feat: add content-visibility: auto state change event (#14373)

* add contentvisibilityautostatechange event

* changeset

* Update .changeset/kind-horses-lay.md

* Update .changeset/kind-horses-lay.md

---------

Co-authored-by: Rich Harris <hello@rich-harris.dev>

.changeset/kind-horses-lay.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+add `contentvisibilityautostatechange` event to element definitions

packages/svelte/elements.d.ts

@@ -60,6 +60,10 @@ export type AnimationEventHandler<T extends EventTarget> = EventHandler<Animatio
 export type TransitionEventHandler<T extends EventTarget> = EventHandler<TransitionEvent, T>;
 export type MessageEventHandler<T extends EventTarget> = EventHandler<MessageEvent, T>;
 export type ToggleEventHandler<T extends EventTarget> = EventHandler<ToggleEvent, T>;
+export type ContentVisibilityAutoStateChangeEventHandler<T extends EventTarget> = EventHandler<
+	ContentVisibilityAutoStateChangeEvent,
+	T
+>;
 
 export type FullAutoFill =
 	| AutoFill
@@ -157,6 +161,20 @@ export interface DOMAttributes<T extends EventTarget> {
 	ontoggle?: ToggleEventHandler<T> | undefined | null;
 	ontogglecapture?: ToggleEventHandler<T> | undefined | null;
 
+	// Content visibility Events
+	'on:contentvisibilityautostatechange'?:
+		| ContentVisibilityAutoStateChangeEventHandler<T>
+		| undefined
+		| null;
+	oncontentvisibilityautostatechange?:
+		| ContentVisibilityAutoStateChangeEventHandler<T>
+		| undefined
+		| null;
+	oncontentvisibilityautostatechangecapture?:
+		| ContentVisibilityAutoStateChangeEventHandler<T>
+		| undefined
+		| null;
+
 	// Keyboard Events
 	'on:keydown'?: KeyboardEventHandler<T> | undefined | null;
 	onkeydown?: KeyboardEventHandler<T> | undefined | null;