Simplified the bit about the && vs & & in borrow expressions

Author: brauliobz

src/expressions/operator-expr.md

@@ -85,17 +85,18 @@ let mut array = [-2, 3, 9];
 }
 ```
 
-For ease of typing, consecutive borrow expressions can be expressed by the
-single token `&&` as if they were separated:
+Even though `&&` is a single token ([the lazy 'and' operator](#lazy-boolean-operators)),
+when used in the context of borrow expressions it works as two borrows:
 
 ```rust
 // same meanings:
 let a = &&  10;
 let a = & & 10;
 
 // same meanings:
-let a = &&  mut 10;
-let a = & & mut 10;
+let a = &&&&  mut 10;
+let a = && && mut 10;
+let a = & & & & mut 10;
 ```
 
 ## The dereference operator