feat: added levenshtein

[Arpita23r]

• Implemented Levenshtein (Edit) Distance algorithm in R to compute the minimum number of edits required to convert one string into another.
• Uses dynamic programming for efficient computation in O(n × m) time.
• Handles insertions, deletions, and substitutions as edit operations.
• Supports case-insensitive input for flexible string comparisons.
• Provides interactive user input for testing and demonstration.
• Outputs the edit distance clearly, allowing easy verification of results.
• Stored file under string_manipulation/edit.distance.R following project structure conventions.

[Copilot]

Pull Request Overview

This PR implements the Levenshtein distance algorithm in R to calculate the minimum number of edit operations (insertions, deletions, substitutions) required to transform one string into another. The implementation uses dynamic programming for efficient O(n×m) computation and includes interactive user input functionality.

• Adds a complete Levenshtein distance function using dynamic programming
• Includes interactive input handling with case-insensitive string comparison
• Provides clear output formatting for the calculated edit distance

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[siriak]

Looks good, thanks!