Implement Ring Map

[waringa-mercy]

@rand00 This are my latest changes. kindly review and advice. Apologies for the confusion by earlier commits

[waringa-mercy]

@rand00 I hope the latest changes are adequate. the map_rev_shortcuicuit is now defined inside Ring module. The map_rev_shortcircuit function takes a function f and a ring r, and applies f to the elements of the ring in reverse order until either f returns None or all elements have been processed. If f returns None for an element, processing stops and the remaining elements are set to None in the copied ring. The function returns a new ring with the modified elements, or with None in the remaining elements if f returned None for one of them.

[waringa-mercy]

@rand00 whenever you can, kindly review the changes i made

[rand00]

I will have a look when I have more time, as the application period is over there is some other Outreachy things that need to be looked at. But again, thank you for contributing!

[waringa-mercy]

@rand00 understood. thank you for the mentorship