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

- 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.
pub fn get(&self) -> Entity {
    self.0
}
```

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

- 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.

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>(