Fix compilation errors on unsupported targets

Also fix typos

Co-authored-by: Jubilee <46493976+workingjubilee@users.noreply.github.com>
Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

library/std/src/sys/anonymous_pipe/mod.rs

@@ -1,16 +1,19 @@
-//! Module for annoymous pipe
+//! Module for anonymous pipe
 //!
 //! ```
 //! #![feature(anonymous_pipe)]
+//!
+//! # #[cfg(miri)] fn main() {}
+//! # #[cfg(not(miri))]
 //! # fn main() -> std::io::Result<()> {
 //! let (reader, writer) = std::pipe::pipe()?;
 //! # Ok(())
 //! # }
 //! ```
 
-use crate::{io, process::Stdio, sys::pipe::AnonPipe};
+use crate::{io, sys::pipe::AnonPipe};
 
-/// Create annoymous pipe that is close-on-exec and blocking.
+/// Create anonymous pipe that is close-on-exec and blocking.
 #[unstable(feature = "anonymous_pipe", issue = "127154")]
 #[inline]
 pub fn pipe() -> io::Result<(PipeReader, PipeWriter)> {
@@ -25,12 +28,12 @@ pub fn pipe() -> io::Result<(PipeReader, PipeWriter)> {
     }
 }
 
-/// Read end of the annoymous pipe.
+/// Read end of the anonymous pipe.
 #[unstable(feature = "anonymous_pipe", issue = "127154")]
 #[derive(Debug)]
 pub struct PipeReader(AnonPipe);
 
-/// Write end of the annoymous pipe.
+/// Write end of the anonymous pipe.
 #[unstable(feature = "anonymous_pipe", issue = "127154")]
 #[derive(Debug)]
 pub struct PipeWriter(AnonPipe);
@@ -137,5 +140,5 @@ mod unix;
 #[cfg(windows)]
 mod windows;
 
-#[cfg(test)]
+#[cfg(all(test, not(miri)))]
 mod tests;

library/std/src/sys/anonymous_pipe/unix.rs

@@ -2,6 +2,7 @@ use super::*;
 
 use crate::{
     os::fd::{AsFd, AsRawFd, BorrowedFd, FromRawFd, IntoRawFd, OwnedFd, RawFd},
+    process::Stdio,
     sys::{
         fd::FileDesc,
         pipe::{anon_pipe, AnonPipe},

library/std/src/sys/anonymous_pipe/windows.rs

@@ -4,6 +4,7 @@ use crate::{
     os::windows::io::{
         AsHandle, AsRawHandle, BorrowedHandle, FromRawHandle, IntoRawHandle, OwnedHandle, RawHandle,
     },
+    process::Stdio,
     sys::{
         handle::Handle,
         pipe::{anon_pipe, AnonPipe, Pipes},

library/std/src/sys/pal/unsupported/pipe.rs

@@ -1,7 +1,16 @@
-use crate::io::{self, BorrowedCursor, IoSlice, IoSliceMut};
+use crate::{
+    fmt,
+    io::{self, BorrowedCursor, IoSlice, IoSliceMut},
+};
 
 pub struct AnonPipe(!);
 
+impl fmt::Debug for AnonPipe {
+    fn fmt(&self, _: &mut fmt::Formatter<'_>) -> fmt::Result {
+        self.0
+    }
+}
+
 impl AnonPipe {
     pub fn try_clone(&self) -> io::Result<Self> {
         self.0