Auto merge of #95960 - jhpratt:remove-rustc_deprecated, r=compiler-errors

Remove `#[rustc_deprecated]`

This removes `#[rustc_deprecated]` and introduces diagnostics to help users to the right direction (that being `#[deprecated]`). All uses of `#[rustc_deprecated]` have been converted. CI is expected to fail initially; this requires #95958, which includes converting `stdarch`.

I plan on following up in a short while (maybe a bootstrap cycle?) removing the diagnostics, as they're only intended to be short-term.

library/std/src/sync/condvar.rs

@@ -303,7 +303,7 @@ impl Condvar {
     /// }
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
-    #[rustc_deprecated(since = "1.6.0", reason = "replaced by `std::sync::Condvar::wait_timeout`")]
+    #[deprecated(since = "1.6.0", note = "replaced by `std::sync::Condvar::wait_timeout`")]
     pub fn wait_timeout_ms<'a, T>(
         &self,
         guard: MutexGuard<'a, T>,

library/std/src/sync/once.rs

@@ -152,9 +152,9 @@ pub struct OnceState {
 /// static START: Once = ONCE_INIT;
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
-#[rustc_deprecated(
+#[deprecated(
     since = "1.38.0",
-    reason = "the `new` function is now preferred",
+    note = "the `new` function is now preferred",
     suggestion = "Once::new()"
 )]
 pub const ONCE_INIT: Once = Once::new();