Rollup merge of rust-lang#126970 - DaniPopes:simplify-str-clone_into,…

… r=cuviper

Simplify `str::clone_into`

Removes an `unsafe` in favor of just using `String` methods.

library/alloc/src/str.rs

@@ -206,15 +206,16 @@ impl BorrowMut<str> for String {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl ToOwned for str {
  type Owned = String;
+
  #[inline]
  fn to_owned(&self) -> String {
  unsafe { String::from_utf8_unchecked(self.as_bytes().to_owned()) }
  }
 
+ #[inline]
  fn clone_into(&self, target: &mut String) {
- let mut b = mem::take(target).into_bytes();
- self.as_bytes().clone_into(&mut b);
- *target = unsafe { String::from_utf8_unchecked(b) }
+ target.clear();
+ target.push_str(self);
  }
 }