Adding smoothsort

[kanishkgits]

Description

Smoothsort is a sorting algorithm that efficiently handles partially sorted data, using specialized heaps (Leonardo heaps) to optimize performance. It’s in-place, with a best-case time complexity of O(n).
Some helpful articles:
Wikipedia: https://en.wikipedia.org/wiki/Smoothsort
GeeksforGeeks: https://www.geeksforgeeks.org/introduction-to-smooth-sort

Type of change

• New feature (non-breaking change which adds functionality)

Checklist:

• I ran below commands using the latest version of rust nightly.
• I ran cargo clippy --all -- -D warnings just before my last commit and fixed any issue that was found.
• I ran cargo fmt just before my last commit.
• I ran cargo test just before my last commit and all tests passed.
• I added my algorithm to the corresponding mod.rs file within its own folder, and in any parent folder(s).
• I added my algorithm to DIRECTORY.md with the correct link.
• I checked COUNTRIBUTING.md and my code follows its guidelines.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.33%. Comparing base (155c767) to head (0c50473).
Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #808      +/-   ##
==========================================
- Coverage   95.33%   95.33%   -0.01%     
==========================================
  Files         310      310              
  Lines       22518    22493      -25     
==========================================
- Hits        21468    21443      -25     
  Misses       1050     1050              

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[vil02]

Why not to use nums.len() directly?

[sozelfist]

Please solve all the issues related to fmt, and clippy and make sure all the tests passed. Please read the CONTRIBUTING guideline before submit the PR.

[kanishkgits]

It's a complex algorithm and I was unable to pass the cargo test :(