search: add search_rotated_sorted_array with tests

[bivekk51]

Description

• Summary: Implemented search_rotated_sorted_array which finds a target in a rotated, ascending-sorted slice and returns Option<usize>.
• Motivation: This algorithm complements existing searching implementations by handling arrays that were rotated after sorting.
• Implementation method: A modified binary search that detects which half of the current range is normally ordered and narrows the search into the half that can contain the target. Assumes distinct elements.
• Complexity: O(log n) time, O(1) extra space.
• Notes: If duplicate elements must be supported, additional checks are required and worst-case complexity may degrade.

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

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 CONTRIBUTING.md and my code follows its guidelines.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.34%. Comparing base (ed7a42e) to head (23b8eb8).

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #922      +/-   ##
==========================================
+ Coverage   95.32%   95.34%   +0.01%     
==========================================
  Files         319      320       +1     
  Lines       20899    20964      +65     
==========================================
+ Hits        19923    19988      +65     
  Misses        976      976              

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