modify std::os docs to be more consistent

> add intra doc links
> add a usage example for the os::windows module

library/std/src/os/unix/ffi/mod.rs

@@ -1,4 +1,4 @@
-//! Unix-specific extension to the primitives in the `std::ffi` module.
+//! Unix-specific extensions to primitives in the [`std::ffi`] module.
 //!
 //! # Examples
 //!
@@ -31,6 +31,8 @@
 //! let bytes = os_str.as_bytes();
 //! assert_eq!(bytes, b"foo");
 //! ```
+//!
+//! [`std::ffi`]: crate::ffi
 
 #![stable(feature = "rust1", since = "1.0.0")]
 

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

@@ -1,4 +1,6 @@
-//! Unix-specific extensions to primitives in the `std::fs` module.
+//! Unix-specific extensions to primitives in the [`std::fs`] module.
+//!
+//! [`std::fs`]: crate::fs
 
 #![stable(feature = "rust1", since = "1.0.0")]
 

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

@@ -4,8 +4,8 @@
 //! exposes Unix-specific functions that would otherwise be inappropriate as
 //! part of the core `std` library.
 //!
-//! It exposes more ways to deal with platform-specific strings (`OsStr`,
-//! `OsString`), allows to set permissions more granularly, extract low-level
+//! It exposes more ways to deal with platform-specific strings ([`OsStr`],
+//! [`OsString`]), allows to set permissions more granularly, extract low-level
 //! file descriptors from files and sockets, and has platform-specific helpers
 //! for spawning processes.
 //!
@@ -24,6 +24,9 @@
 //!     Ok(())
 //! }
 //! ```
+//!
+//! [`OsStr`]: crate::ffi::OsStr
+//! [`OsString`]: crate::ffi::OsString
 
 #![stable(feature = "rust1", since = "1.0.0")]
 #![doc(cfg(unix))]

library/std/src/os/unix/net/mod.rs

@@ -1,4 +1,4 @@
-//! Unix-specific networking functionality
+//! Unix-specific networking functionality.
 
 #![stable(feature = "unix_socket", since = "1.10.0")]
 

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

@@ -1,4 +1,6 @@
-//! Unix-specific extensions to primitives in the `std::process` module.
+//! Unix-specific extensions to primitives in the [`std::process`] module.
+//!
+//! [`std::process`]: crate::process
 
 #![stable(feature = "rust1", since = "1.0.0")]
 

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

@@ -1,4 +1,6 @@
-//! Unix-specific extensions to primitives in the `std::thread` module.
+//! Unix-specific extensions to primitives in the [`std::thread`] module.
+//!
+//! [`std::thread`]: crate::thread
 
 #![stable(feature = "thread_extensions", since = "1.9.0")]