Add Jaccard Similarity

[Kalkwst]

• [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
• [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
• [x] I have made corresponding changes to the README.md

[codecov[bot]]

Codecov Report

All modified lines are covered by tests :white_check_mark:

Comparison is base (0677638) 96.03% compared to head (d9781f8) 96.04%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #419 +/- ## ========================================== + Coverage 96.03% 96.04% +0.01% ========================================== Files 228 230 +2 Lines 9562 9592 +30 ========================================== + Hits 9183 9213 +30 Misses 379 379 ``` | [Files](https://app.codecov.io/gh/TheAlgorithms/C-Sharp/pull/419?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=TheAlgorithms) | Coverage Δ | | |---|---|---| | [Algorithms/Strings/Similarity/JaccardDistance.cs](https://app.codecov.io/gh/TheAlgorithms/C-Sharp/pull/419?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=TheAlgorithms#diff-QWxnb3JpdGhtcy9TdHJpbmdzL1NpbWlsYXJpdHkvSmFjY2FyZERpc3RhbmNlLmNz) | `100.00% <100.00%> (ø)` | | | [Algorithms/Strings/Similarity/JaccardSimilarity.cs](https://app.codecov.io/gh/TheAlgorithms/C-Sharp/pull/419?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=TheAlgorithms#diff-QWxnb3JpdGhtcy9TdHJpbmdzL1NpbWlsYXJpdHkvSmFjY2FyZFNpbWlsYXJpdHkuY3M=) | `100.00% <100.00%> (ø)` | |

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