Deprecate the AsciiExt trait in favor of inherent methods

[SimonSapin]

The trait and some of its methods are stable and will remain.
Some of the newer methods are unstable and can be removed later.

Fixes #39658

[SimonSapin]

These methods are removed on str and [u8] in favor of explicit Iterator::all: #39658 (comment)

[alexcrichton]

@bors: r+

[bors]

📌 Commit dbc0c43 has been approved by alexcrichton

[kennytm]

@bors r-

Failed to build stage0-std on Windows.

error[E0624]: method `make_ascii_uppercase` is private
  --> libstd\sys\windows\process.rs:47:13
   |
47 |         buf.make_ascii_uppercase();
   |             ^^^^^^^^^^^^^^^^^^^^

[SimonSapin]

I had turned a trait impl into inherent methods, but forgot to make them public. Additional diff squashed into the commit just now:

diff --git a/src/libstd/sys_common/wtf8.rs b/src/libstd/sys_common/wtf8.rs
index 175107bdc4..78b2bb5fe6 100644
--- a/src/libstd/sys_common/wtf8.rs
+++ b/src/libstd/sys_common/wtf8.rs
@@ -871,21 +871,21 @@ impl Hash for Wtf8 {
 }
 
 impl Wtf8 {
-    fn is_ascii(&self) -> bool {
+    pub fn is_ascii(&self) -> bool {
         self.bytes.is_ascii()
     }
-    fn to_ascii_uppercase(&self) -> Wtf8Buf {
+    pub fn to_ascii_uppercase(&self) -> Wtf8Buf {
         Wtf8Buf { bytes: self.bytes.to_ascii_uppercase() }
     }
-    fn to_ascii_lowercase(&self) -> Wtf8Buf {
+    pub fn to_ascii_lowercase(&self) -> Wtf8Buf {
         Wtf8Buf { bytes: self.bytes.to_ascii_lowercase() }
     }
-    fn eq_ignore_ascii_case(&self, other: &Wtf8) -> bool {
+    pub fn eq_ignore_ascii_case(&self, other: &Wtf8) -> bool {
         self.bytes.eq_ignore_ascii_case(&other.bytes)
     }
 
-    fn make_ascii_uppercase(&mut self) { self.bytes.make_ascii_uppercase() }
-    fn make_ascii_lowercase(&mut self) { self.bytes.make_ascii_lowercase() }
+    pub fn make_ascii_uppercase(&mut self) { self.bytes.make_ascii_uppercase() }
+    pub fn make_ascii_lowercase(&mut self) { self.bytes.make_ascii_lowercase() }
 }
 
 #[cfg(test)]

[SimonSapin]

@bors: r=alexcrichton

[bors]

📌 Commit c09b9f9 has been approved by alexcrichton

[bors]

🌲 The tree is currently closed for pull requests below priority 30, this pull request will be tested once the tree is reopened