Rollup merge of rust-lang#62942 - KevinWMatthews:condvar_docs_match_e…

…rgo, r=sfackler

Use match ergonomics in Condvar documentation

Documentation was written before match ergonomics was merged. See rust-lang#62857.

In short, replaces

```rust
let &(ref lock, ref cvar) = &*pair;
```

with

```rust
let (lock, cvar) = &*pair
```

in the docs of `std::sync::Condvar`.

src/libstd/sync/condvar.rs

@@ -36,7 +36,7 @@ impl WaitTimeoutResult {
     /// let pair2 = pair.clone();
     ///
     /// thread::spawn(move|| {
-    ///     let &(ref lock, ref cvar) = &*pair2;
+    ///     let (lock, cvar) = &*pair2;
     ///
     ///     // Let's wait 20 milliseconds before notifying the condvar.
     ///     thread::sleep(Duration::from_millis(20));
@@ -48,7 +48,7 @@ impl WaitTimeoutResult {
     /// });
     ///
     /// // Wait for the thread to start up.
-    /// let &(ref lock, ref cvar) = &*pair;
+    /// let (lock, cvar) = &*pair;
     /// let mut started = lock.lock().unwrap();
     /// loop {
     ///     // Let's put a timeout on the condvar's wait.
@@ -94,15 +94,15 @@ impl WaitTimeoutResult {
 ///
 /// // Inside of our lock, spawn a new thread, and then wait for it to start.
 /// thread::spawn(move|| {
-///     let &(ref lock, ref cvar) = &*pair2;
+///     let (lock, cvar) = &*pair2;
 ///     let mut started = lock.lock().unwrap();
 ///     *started = true;
 ///     // We notify the condvar that the value has changed.
 ///     cvar.notify_one();
 /// });
 ///
 /// // Wait for the thread to start up.
-/// let &(ref lock, ref cvar) = &*pair;
+/// let (lock, cvar) = &*pair;
 /// let mut started = lock.lock().unwrap();
 /// while !*started {
 ///     started = cvar.wait(started).unwrap();
@@ -180,15 +180,15 @@ impl Condvar {
     /// let pair2 = pair.clone();
     ///
     /// thread::spawn(move|| {
-    ///     let &(ref lock, ref cvar) = &*pair2;
+    ///     let (lock, cvar) = &*pair2;
     ///     let mut started = lock.lock().unwrap();
     ///     *started = true;
     ///     // We notify the condvar that the value has changed.
     ///     cvar.notify_one();
     /// });
     ///
     /// // Wait for the thread to start up.
-    /// let &(ref lock, ref cvar) = &*pair;
+    /// let (lock, cvar) = &*pair;
     /// let mut started = lock.lock().unwrap();
     /// // As long as the value inside the `Mutex<bool>` is `false`, we wait.
     /// while !*started {
@@ -245,15 +245,15 @@ impl Condvar {
     /// let pair2 = pair.clone();
     ///
     /// thread::spawn(move|| {
-    ///     let &(ref lock, ref cvar) = &*pair2;
+    ///     let (lock, cvar) = &*pair2;
     ///     let mut started = lock.lock().unwrap();
     ///     *started = true;
     ///     // We notify the condvar that the value has changed.
     ///     cvar.notify_one();
     /// });
     ///
     /// // Wait for the thread to start up.
-    /// let &(ref lock, ref cvar) = &*pair;
+    /// let (lock, cvar) = &*pair;
     /// // As long as the value inside the `Mutex<bool>` is `false`, we wait.
     /// let _guard = cvar.wait_until(lock.lock().unwrap(), |started| { *started }).unwrap();
     /// ```
@@ -301,15 +301,15 @@ impl Condvar {
     /// let pair2 = pair.clone();
     ///
     /// thread::spawn(move|| {
-    ///     let &(ref lock, ref cvar) = &*pair2;
+    ///     let (lock, cvar) = &*pair2;
     ///     let mut started = lock.lock().unwrap();
     ///     *started = true;
     ///     // We notify the condvar that the value has changed.
     ///     cvar.notify_one();
     /// });
     ///
     /// // Wait for the thread to start up.
-    /// let &(ref lock, ref cvar) = &*pair;
+    /// let (lock, cvar) = &*pair;
     /// let mut started = lock.lock().unwrap();
     /// // As long as the value inside the `Mutex<bool>` is `false`, we wait.
     /// loop {
@@ -374,15 +374,15 @@ impl Condvar {
     /// let pair2 = pair.clone();
     ///
     /// thread::spawn(move|| {
-    ///     let &(ref lock, ref cvar) = &*pair2;
+    ///     let (lock, cvar) = &*pair2;
     ///     let mut started = lock.lock().unwrap();
     ///     *started = true;
     ///     // We notify the condvar that the value has changed.
     ///     cvar.notify_one();
     /// });
     ///
     /// // wait for the thread to start up
-    /// let &(ref lock, ref cvar) = &*pair;
+    /// let (lock, cvar) = &*pair;
     /// let mut started = lock.lock().unwrap();
     /// // as long as the value inside the `Mutex<bool>` is `false`, we wait
     /// loop {
@@ -449,15 +449,15 @@ impl Condvar {
     /// let pair2 = pair.clone();
     ///
     /// thread::spawn(move|| {
-    ///     let &(ref lock, ref cvar) = &*pair2;
+    ///     let (lock, cvar) = &*pair2;
     ///     let mut started = lock.lock().unwrap();
     ///     *started = true;
     ///     // We notify the condvar that the value has changed.
     ///     cvar.notify_one();
     /// });
     ///
     /// // wait for the thread to start up
-    /// let &(ref lock, ref cvar) = &*pair;
+    /// let (lock, cvar) = &*pair;
     /// let result = cvar.wait_timeout_until(
     ///     lock.lock().unwrap(),
     ///     Duration::from_millis(100),
@@ -508,15 +508,15 @@ impl Condvar {
     /// let pair2 = pair.clone();
     ///
     /// thread::spawn(move|| {
-    ///     let &(ref lock, ref cvar) = &*pair2;
+    ///     let (lock, cvar) = &*pair2;
     ///     let mut started = lock.lock().unwrap();
     ///     *started = true;
     ///     // We notify the condvar that the value has changed.
     ///     cvar.notify_one();
     /// });
     ///
     /// // Wait for the thread to start up.
-    /// let &(ref lock, ref cvar) = &*pair;
+    /// let (lock, cvar) = &*pair;
     /// let mut started = lock.lock().unwrap();
     /// // As long as the value inside the `Mutex<bool>` is `false`, we wait.
     /// while !*started {
@@ -548,15 +548,15 @@ impl Condvar {
     /// let pair2 = pair.clone();
     ///
     /// thread::spawn(move|| {
-    ///     let &(ref lock, ref cvar) = &*pair2;
+    ///     let (lock, cvar) = &*pair2;
     ///     let mut started = lock.lock().unwrap();
     ///     *started = true;
     ///     // We notify the condvar that the value has changed.
     ///     cvar.notify_all();
     /// });
     ///
     /// // Wait for the thread to start up.
-    /// let &(ref lock, ref cvar) = &*pair;
+    /// let (lock, cvar) = &*pair;
     /// let mut started = lock.lock().unwrap();
     /// // As long as the value inside the `Mutex<bool>` is `false`, we wait.
     /// while !*started {