Rollup merge of rust-lang#130713 - bjoernager:const-char-make-ascii, r=Noratrieb

Mark `u8::make_ascii_uppercase` and `u8::make_ascii_lowercase` as const.

Relevant tracking issue: rust-lang#130698

This PR extends rust-lang#130697 by also marking the `make_ascii_uppercase` and `make_ascii_lowercase` methods in `u8` as const.

The `const_char_make_ascii` feature gate is additionally renamed to `const_make_ascii`.

Author: matthiaskrgr

core/src/char/methods.rs

@@ -1279,7 +1279,7 @@ impl char {
     ///
     /// [`to_ascii_uppercase()`]: #method.to_ascii_uppercase
     #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
-    #[rustc_const_unstable(feature = "const_char_make_ascii", issue = "130698")]
+    #[rustc_const_unstable(feature = "const_make_ascii", issue = "130698")]
     #[inline]
     pub const fn make_ascii_uppercase(&mut self) {
         *self = self.to_ascii_uppercase();
@@ -1305,7 +1305,7 @@ impl char {
     ///
     /// [`to_ascii_lowercase()`]: #method.to_ascii_lowercase
     #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
-    #[rustc_const_unstable(feature = "const_char_make_ascii", issue = "130698")]
+    #[rustc_const_unstable(feature = "const_make_ascii", issue = "130698")]
     #[inline]
     pub const fn make_ascii_lowercase(&mut self) {
         *self = self.to_ascii_lowercase();

core/src/num/mod.rs

@@ -624,8 +624,9 @@ impl u8 {
     ///
     /// [`to_ascii_uppercase`]: Self::to_ascii_uppercase
     #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
+    #[rustc_const_unstable(feature = "const_make_ascii", issue = "130698")]
     #[inline]
-    pub fn make_ascii_uppercase(&mut self) {
+    pub const fn make_ascii_uppercase(&mut self) {
         *self = self.to_ascii_uppercase();
     }
 
@@ -649,8 +650,9 @@ impl u8 {
     ///
     /// [`to_ascii_lowercase`]: Self::to_ascii_lowercase
     #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
+    #[rustc_const_unstable(feature = "const_make_ascii", issue = "130698")]
     #[inline]
-    pub fn make_ascii_lowercase(&mut self) {
+    pub const fn make_ascii_lowercase(&mut self) {
         *self = self.to_ascii_lowercase();
     }