Rollup merge of #88177 - joshtriplett:stabilize-chroot, r=m-ou-se

Stabilize std::os::unix::fs::chroot

I've verified that this works as documented, and I've tested it in (a nightly
build of) production software as a replacement for an unsafe call to
`libc::chroot`. It's been available in nightly for a few releases. I think it's
ready to stabilize.

---

Tracking issue: #84715

library/std/src/os/unix/fs.rs

@@ -934,7 +934,6 @@ impl DirBuilderExt for fs::DirBuilder {
 /// # Examples
 ///
 /// ```no_run
-/// #![feature(unix_chroot)]
 /// use std::os::unix::fs;
 ///
 /// fn main() -> std::io::Result<()> {
@@ -944,7 +943,7 @@ impl DirBuilderExt for fs::DirBuilder {
 ///     Ok(())
 /// }
 /// ```
-#[unstable(feature = "unix_chroot", issue = "84715")]
+#[stable(feature = "unix_chroot", since = "1.56.0")]
 #[cfg(not(any(target_os = "fuchsia", target_os = "vxworks")))]
 pub fn chroot<P: AsRef<Path>>(dir: P) -> io::Result<()> {
     sys::fs::chroot(dir.as_ref())