(Fix IDE0180) Favor modern tuple swap over temporary variables.

C# 7 brought tuple types, which allowed for very clean and efficient swapping of values. This pull request replaces temporary variable assignments across the repository with said feature:

// === Example ===
// before:
int temp = numbers[0];
numbers[0] = numbers[1];
numbers[1] = temp;
// after
(numbers[1], numbers[0]) = (numbers[0], numbers[1]);

See more details on the code issue here.

[x] I have performed a self-review of my code
[x] My code follows the style guidelines of this project
[x] I have added tests that prove my fix is effective or that my feature works (no new features)
[x] New and existing unit tests pass locally with my changes
[x] Comments in areas I changed are up to date
[x] I have added comments to hard-to-understand areas of my code (my changes makes stuff more understandable)
[x] I have made corresponding changes to the README.md (nothing new)

TheAlgorithms / C-Sharp

(Fix IDE0180) Favor modern tuple swap over temporary variables. #401