Rollup merge of #84084 - m-ou-se:stabilize-zero, r=scottmcm

Stabilize duration_zero.

FCP here: #73544 (comment)

Author: Dylan-DPC

library/core/src/time.rs

@@ -124,14 +124,13 @@ impl Duration {
     /// # Examples
     ///
     /// ```
-    /// #![feature(duration_zero)]
     /// use std::time::Duration;
     ///
     /// let duration = Duration::ZERO;
     /// assert!(duration.is_zero());
     /// assert_eq!(duration.as_nanos(), 0);
     /// ```
-    #[unstable(feature = "duration_zero", issue = "73544")]
+    #[stable(feature = "duration_zero", since = "1.53.0")]
     pub const ZERO: Duration = Duration::from_nanos(0);
 
     /// The maximum duration.
@@ -269,7 +268,6 @@ impl Duration {
     /// # Examples
     ///
     /// ```
-    /// #![feature(duration_zero)]
     /// use std::time::Duration;
     ///
     /// assert!(Duration::ZERO.is_zero());
@@ -281,7 +279,8 @@ impl Duration {
     /// assert!(!Duration::from_nanos(1).is_zero());
     /// assert!(!Duration::from_secs(1).is_zero());
     /// ```
-    #[unstable(feature = "duration_zero", issue = "73544")]
+    #[stable(feature = "duration_zero", since = "1.53.0")]
+    #[rustc_const_stable(feature = "duration_zero", since = "1.53.0")]
     #[inline]
     pub const fn is_zero(&self) -> bool {
         self.secs == 0 && self.nanos == 0
@@ -536,7 +535,6 @@ impl Duration {
     /// # Examples
     ///
     /// ```
-    /// #![feature(duration_zero)]
     /// use std::time::Duration;
     ///
     /// assert_eq!(Duration::new(0, 1).saturating_sub(Duration::new(0, 0)), Duration::new(0, 1));

library/core/tests/lib.rs

@@ -24,7 +24,6 @@
 #![feature(div_duration)]
 #![feature(duration_consts_2)]
 #![feature(duration_constants)]
-#![feature(duration_zero)]
 #![feature(exact_size_is_empty)]
 #![feature(extern_types)]
 #![feature(flt2dec)]

library/std/src/lib.rs

@@ -261,7 +261,6 @@
 #![cfg_attr(not(bootstrap), feature(doc_notable_trait))]
 #![feature(dropck_eyepatch)]
 #![feature(duration_constants)]
-#![feature(duration_zero)]
 #![feature(edition_panic)]
 #![feature(exact_size_is_empty)]
 #![feature(exhaustive_patterns)]