Add #[deprecated(since = "0.16.0", ...)] to items missing it (#18702)

# Objective

- The `#[deprecated]` attributes supports a `since` field, which
documents in which version an item was deprecated. This field is visible
in `rustdoc`.
- We inconsistently use `since` throughout the project.

For an example of what `since` renders as, take a look at
`ChildOf::get()`:

```rust
/// The parent entity of this child entity.
#[deprecated(since = "0.16.0", note = "Use child_of.parent() instead")]
#[inline]
pub fn get(&self) -> Entity {
    self.0
}
```


![image](https://github.com/user-attachments/assets/2ea5d8c9-2eab-430a-9a1c-421f315ff123)


## Solution

- Add `since = "0.16.0"` to all `#[deprecated]` attributes that do not
already use it.
- Add an example of deprecating a struct with the `since` field in the
migration guide document.

I would appreciate if this could be included in 0.16's release, as its a
low-risk documentation improvement that is valuable for the release, but
I'd understand if this was cut.

## Testing

You can use `cargo doc` to inspect the rendered form of
`#[deprecated(since = "0.16.0", ...)]`.

crates/bevy_asset/src/handle.rs

@@ -150,7 +150,10 @@ impl<T: Asset> Clone for Handle<T> {
 
 impl<A: Asset> Handle<A> {
     /// Create a new [`Handle::Weak`] with the given [`u128`] encoding of a [`Uuid`].
-    #[deprecated = "use the `weak_handle!` macro with a UUID string instead"]
+    #[deprecated(
+        since = "0.16.0",
+        note = "use the `weak_handle!` macro with a UUID string instead"
+    )]
     pub const fn weak_from_u128(value: u128) -> Self {
         Handle::Weak(AssetId::Uuid {
             uuid: Uuid::from_u128(value),

crates/bevy_ecs/src/entity/mod.rs

@@ -244,6 +244,7 @@ impl Hash for Entity {
 }
 
 #[deprecated(
+    since = "0.16.0",
     note = "This is exclusively used with the now deprecated `Entities::alloc_at_without_replacement`."
 )]
 pub(crate) enum AllocAtWithoutReplacement {
@@ -694,6 +695,7 @@ impl Entities {
     /// Returns the location of the entity currently using the given ID, if any. Location should be
     /// written immediately.
     #[deprecated(
+        since = "0.16.0",
         note = "This can cause extreme performance problems when used after freeing a large number of entities and requesting an arbitrary entity. See #18054 on GitHub."
     )]
     pub fn alloc_at(&mut self, entity: Entity) -> Option<EntityLocation> {
@@ -728,6 +730,7 @@ impl Entities {
     ///
     /// Returns the location of the entity currently using the given ID, if any.
     #[deprecated(
+        since = "0.16.0",
         note = "This can cause extreme performance problems when used after freeing a large number of entities and requesting an arbitrary entity. See #18054 on GitHub."
     )]
     #[expect(

crates/bevy_ecs/src/system/query.rs

@@ -1532,7 +1532,10 @@ impl<'w, 's, D: QueryData, F: QueryFilter> Query<'w, 's, D, F> {
     /// - [`get_many`](Self::get_many) for the non-panicking version.
     #[inline]
     #[track_caller]
-    #[deprecated(note = "Use `get_many` instead and handle the Result.")]
+    #[deprecated(
+        since = "0.16.0",
+        note = "Use `get_many` instead and handle the Result."
+    )]
     pub fn many<const N: usize>(&self, entities: [Entity; N]) -> [ROQueryItem<'_, D>; N] {
         match self.get_many(entities) {
             Ok(items) => items,
@@ -1929,7 +1932,10 @@ impl<'w, 's, D: QueryData, F: QueryFilter> Query<'w, 's, D, F> {
     /// - [`many`](Self::many) to get read-only query items.
     #[inline]
     #[track_caller]
-    #[deprecated(note = "Use `get_many_mut` instead and handle the Result.")]
+    #[deprecated(
+        since = "0.16.0",
+        note = "Use `get_many_mut` instead and handle the Result."
+    )]
     pub fn many_mut<const N: usize>(&mut self, entities: [Entity; N]) -> [D::Item<'_>; N] {
         match self.get_many_mut(entities) {
             Ok(items) => items,
@@ -1993,7 +1999,7 @@ impl<'w, 's, D: QueryData, F: QueryFilter> Query<'w, 's, D, F> {
     }
 
     /// A deprecated alias for [`single`](Self::single).
-    #[deprecated(note = "Please use `single` instead")]
+    #[deprecated(since = "0.16.0", note = "Please use `single` instead")]
     pub fn get_single(&self) -> Result<ROQueryItem<'_, D>, QuerySingleError> {
         self.single()
     }
@@ -2028,7 +2034,7 @@ impl<'w, 's, D: QueryData, F: QueryFilter> Query<'w, 's, D, F> {
     }
 
     /// A deprecated alias for [`single_mut`](Self::single_mut).
-    #[deprecated(note = "Please use `single_mut` instead")]
+    #[deprecated(since = "0.16.0", note = "Please use `single_mut` instead")]
     pub fn get_single_mut(&mut self) -> Result<D::Item<'_>, QuerySingleError> {
         self.single_mut()
     }

crates/bevy_ecs/src/world/mod.rs

@@ -2253,6 +2253,7 @@ impl World {
     /// ```
     #[track_caller]
     #[deprecated(
+        since = "0.16.0",
         note = "This can cause extreme performance problems when used with lots of arbitrary free entities. See #18054 on GitHub."
     )]
     pub fn insert_or_spawn_batch<I, B>(&mut self, iter: I) -> Result<(), Vec<Entity>>
@@ -2272,6 +2273,7 @@ impl World {
     /// as a command.
     #[inline]
     #[deprecated(
+        since = "0.16.0",
         note = "This can cause extreme performance problems when used with lots of arbitrary free entities. See #18054 on GitHub."
     )]
     pub(crate) fn insert_or_spawn_batch_with_caller<I, B>(

release-content/migration_guides.md

@@ -50,3 +50,8 @@ Rust provides a very helpful [`#[deprecated]` attribute](https://doc.rust-lang.o
 This can be a nice a tool to ease migrations, because it downgrades errors to warnings and makes the migration information available right in the user's IDE.
 
 However, it's not always possible to use this attribute, and Bevy does not consider it to be a substitute to a migration guide entry.
+
+```rust
+#[deprecated(since = "0.17.0", note = "This message will appear in the deprecation warning.")]
+struct MyStruct;
+```