Fixed the confusion around expression and the block expression of while let

Author: brauliobz

src/expressions/loop-expr.md

@@ -74,8 +74,8 @@ while i < 10 {
 
 A `while let` loop is semantically similar to a `while` loop but in place of a
 condition expression it expects the keyword `let` followed by a refutable
-pattern, an `=` and a block expression. If the value of the expression on the right
-hand side of the `=` matches the pattern, the loop body block executes then
+pattern, an `=`, an expression and a block expression. If the value of the expression on
+the right hand side of the `=` matches the pattern, the loop body block executes then
 control returns to the pattern matching statement. Otherwise, the while
 expression completes.