added nthFibonacciNumber and XorSwap

[sethivansh6]

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• [ ] Yes, this task assigned to me.
• [x] My code follows the style guidelines(Clean Code) of this project
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[sethivansh6]

I have added nthFibonacciNumber and XorSwap. I can add more code if you allow me to do so.

[aayushi-droid]

Unassigned Pull Request

[aayushi-droid]

The task was assigned to someone else and merged