[Typo]- In chapter Arrays in the section of loops we have to change `number` to `index`

[sajwan05]

In chapter Arrays 's section Loops there in sentence The for..of doesn’t give access to the **number** of the current element, just its value, but in most cases that’s enough. And it’s shorter.
Instead of number we have to use index.
Because using number is not really telling us we're talking about index or number (which can be value)

[X] I would love to work on this issue.