Update since to correct release

`const_ordering` will stabilize in version 1.48.0

Author: CDirkx

library/core/src/cmp.rs

@@ -356,7 +356,7 @@ impl Ordering {
     /// ```
     #[inline]
     #[must_use]
-    #[rustc_const_stable(feature = "const_ordering", since = "1.47.0")]
+    #[rustc_const_stable(feature = "const_ordering", since = "1.48.0")]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub const fn reverse(self) -> Ordering {
         match self {
@@ -395,7 +395,7 @@ impl Ordering {
     /// ```
     #[inline]
     #[must_use]
-    #[rustc_const_stable(feature = "const_ordering", since = "1.47.0")]
+    #[rustc_const_stable(feature = "const_ordering", since = "1.48.0")]
     #[stable(feature = "ordering_chaining", since = "1.17.0")]
     pub const fn then(self, other: Ordering) -> Ordering {
         match self {