Rollup merge of #73959 - GuillaumeGomez:cleanup-e0716, r=Dylan-DPC

Clean up E0716 explanation

r? @Dylan-DPC

src/librustc_error_codes/error_codes/E0716.md

@@ -1,5 +1,4 @@
-This error indicates that a temporary value is being dropped
-while a borrow is still in active use.
+A temporary value is being dropped while a borrow is still in active use.
 
 Erroneous code example:
 
@@ -11,12 +10,11 @@ let p = bar(&foo());
 let q = *p;
 ```
 
-Here, the expression `&foo()` is borrowing the expression
-`foo()`. As `foo()` is a call to a function, and not the name of
-a variable, this creates a **temporary** -- that temporary stores
-the return value from `foo()` so that it can be borrowed.
-You could imagine that `let p = bar(&foo());` is equivalent
-to this:
+Here, the expression `&foo()` is borrowing the expression `foo()`. As `foo()` is
+a call to a function, and not the name of a variable, this creates a
+**temporary** -- that temporary stores the return value from `foo()` so that it
+can be borrowed. You could imagine that `let p = bar(&foo());` is equivalent to
+this:
 
 ```compile_fail,E0597
 # fn foo() -> i32 { 22 }
@@ -28,16 +26,14 @@ let p = {
 let q = p;
 ```
 
-Whenever a temporary is created, it is automatically dropped (freed)
-according to fixed rules. Ordinarily, the temporary is dropped
-at the end of the enclosing statement -- in this case, after the `let`.
-This is illustrated in the example above by showing that `tmp` would
-be freed as we exit the block.
+Whenever a temporary is created, it is automatically dropped (freed) according
+to fixed rules. Ordinarily, the temporary is dropped at the end of the enclosing
+statement -- in this case, after the `let`. This is illustrated in the example
+above by showing that `tmp` would be freed as we exit the block.
 
-To fix this problem, you need to create a local variable
-to store the value in rather than relying on a temporary.
-For example, you might change the original program to
-the following:
+To fix this problem, you need to create a local variable to store the value in
+rather than relying on a temporary. For example, you might change the original
+program to the following:
 
 ```
 fn foo() -> i32 { 22 }
@@ -47,16 +43,15 @@ let p = bar(&value);
 let q = *p;
 ```
 
-By introducing the explicit `let value`, we allocate storage
-that will last until the end of the enclosing block (when `value`
-goes out of scope). When we borrow `&value`, we are borrowing a
-local variable that already exists, and hence no temporary is created.
+By introducing the explicit `let value`, we allocate storage that will last
+until the end of the enclosing block (when `value` goes out of scope). When we
+borrow `&value`, we are borrowing a local variable that already exists, and
+hence no temporary is created.
 
-Temporaries are not always dropped at the end of the enclosing
-statement. In simple cases where the `&` expression is immediately
-stored into a variable, the compiler will automatically extend
-the lifetime of the temporary until the end of the enclosing
-block. Therefore, an alternative way to fix the original
+Temporaries are not always dropped at the end of the enclosing statement. In
+simple cases where the `&` expression is immediately stored into a variable, the
+compiler will automatically extend the lifetime of the temporary until the end
+of the enclosing block. Therefore, an alternative way to fix the original
 program is to write `let tmp = &foo()` and not `let tmp = foo()`:
 
 ```
@@ -67,10 +62,10 @@ let p = bar(value);
 let q = *p;
 ```
 
-Here, we are still borrowing `foo()`, but as the borrow is assigned
-directly into a variable, the temporary will not be dropped until
-the end of the enclosing block. Similar rules apply when temporaries
-are stored into aggregate structures like a tuple or struct:
+Here, we are still borrowing `foo()`, but as the borrow is assigned directly
+into a variable, the temporary will not be dropped until the end of the
+enclosing block. Similar rules apply when temporaries are stored into aggregate
+structures like a tuple or struct:
 
 ```
 // Here, two temporaries are created, but