Describe your change:

• [Yes ] Add an algorithm?
• Fix a bug or typo in an existing algorithm?
• Add or change doctests? -- Note: Please avoid changing both code and tests in a single pull request.
• Documentation change?

Checklist:

• [Yes ] I have read CONTRIBUTING.md.
• [Yes ] This pull request is all my own work -- I have not plagiarized.
• [Yes ] I know that pull requests will not be merged if they fail the automated tests.
• [ Yes] This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• [ Yes] All new Python files are placed inside an existing directory.
• [ Yes] All filenames are in all lowercase characters with no spaces or dashes.
• [ Yes] All functions and variable names follow Python naming conventions.
• [ Yes] All function parameters and return values are annotated with Python type hints.
• [ Yes] All functions have doctests that pass the automated testing.
• [ Yes] All new algorithms include at least one URL that points to Wikipedia or another similar explanation.
• [ Yes] If this pull request resolves one or more open issues then the description above includes the issue number(s) with a closing keyword: "Fixes #ISSUE-NUMBER".

Fixes #13569

Description
Added a new script ascii_to_char.py under the conversions module.
The function ascii_to_char(ascii_value: int) converts an ASCII integer to its corresponding character.
Example
ascii_to_char(65)
'A'

Details
Added input validation for range 0–127
Included doctest for quick verification
Code follows TheAlgorithms style and documentation format