Rollup merge of rust-lang#33326 - birkenfeld:issue-33321, r=GuillaumeGomez

std::thread docs: spawn() does not return a Thread anymore

Also move the "Thread type" section down a bit, since it is not so important anymore.

Fixes: rust-lang#33321

Author: steveklabnik

src/libstd/thread/mod.rs

@@ -13,7 +13,8 @@
 //! ## The threading model
 //!
 //! An executing Rust program consists of a collection of native OS threads,
-//! each with their own stack and local state.
+//! each with their own stack and local state. Threads can be named, and
+//! provide some built-in support for low-level synchronization.
 //!
 //! Communication between threads can be done through
 //! [channels](../../std/sync/mpsc/index.html), Rust's message-passing
@@ -37,20 +38,6 @@
 //! convenient facilities for automatically waiting for the termination of a
 //! child thread (i.e., join).
 //!
-//! ## The `Thread` type
-//!
-//! Threads are represented via the `Thread` type, which you can
-//! get in one of two ways:
-//!
-//! * By spawning a new thread, e.g. using the `thread::spawn` function.
-//! * By requesting the current thread, using the `thread::current` function.
-//!
-//! Threads can be named, and provide some built-in support for low-level
-//! synchronization (described below).
-//!
-//! The `thread::current()` function is available even for threads not spawned
-//! by the APIs of this module.
-//!
 //! ## Spawning a thread
 //!
 //! A new thread can be spawned using the `thread::spawn` function:
@@ -99,6 +86,18 @@
 //! });
 //! ```
 //!
+//! ## The `Thread` type
+//!
+//! Threads are represented via the `Thread` type, which you can get in one of
+//! two ways:
+//!
+//! * By spawning a new thread, e.g. using the `thread::spawn` function, and
+//!   calling `thread()` on the `JoinHandle`.
+//! * By requesting the current thread, using the `thread::current` function.
+//!
+//! The `thread::current()` function is available even for threads not spawned
+//! by the APIs of this module.
+//!
 //! ## Blocking support: park and unpark
 //!
 //! Every thread is equipped with some basic low-level blocking support, via the