added fibonacci using formula along with test cases (#1358)

* added fibonacci using formula along with test cases

* updated the changes

* added jest's each in test cases

* added jest's each for testing

* returned inline value

* removed redundant comment

* hoisted the variables

* Use shorthand

* considered adding resource of the formula

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Co-authored-by: madhuredra <madhuredra.tiwari@zemosolabs.com>
Co-authored-by: Lars Müller <34514239+appgurueu@users.noreply.github.com>