Add any_content_changed_of_output_assets (vercel/turborepo#5513)

### Description

Required for #52259

### Testing Instructions

N/A

Co-authored-by: Tobias Koppers <sokra@users.noreply.github.com>

crates/turbopack-core/src/changed.rs

@@ -6,6 +6,7 @@ use turbo_tasks::{
 
 use crate::{
     asset::{Asset, AssetVc},
+    output::OutputAssetsVc,
     reference::all_referenced_assets,
 };
 
@@ -33,6 +34,20 @@ pub async fn any_content_changed(root: AssetVc) -> Result<CompletionVc> {
     Ok(CompletionsVc::cell(completions).completed())
 }
 
+/// Returns a completion that changes when any content of any asset in the given
+/// output asset graphs changes.
+#[turbo_tasks::function]
+pub async fn any_content_changed_of_output_assets(roots: OutputAssetsVc) -> Result<CompletionVc> {
+    Ok(CompletionsVc::cell(
+        roots
+            .await?
+            .iter()
+            .map(|&a| any_content_changed(a.into()))
+            .collect(),
+    )
+    .completed())
+}
+
 /// Returns a completion that changes when the content of the given asset
 /// changes.
 #[turbo_tasks::function]