Add hollow_diamond_alphabet function for printing alphabet diamond patterns.

[AniketPandey22]

Describe your change:

Certainly. I'll summarize the changes made to the program:

1. Input Validation Enhancement:

   • More comprehensive input checks were added in the hollow_diamond_alphabet function.
   • A new get_valid_input function was created to handle user input separately.

2. Error Handling Improvement:

   • Implemented specific error messages for different types of invalid input.
   • Added try-except block to catch ValueError for non-integer inputs.

3. User Interface Updates:

   • Added option for the user to quit the program by entering 'q'.
   • Implemented a loop to allow multiple pattern generations in one session.
   • Included success messages after successful pattern printing.

4. Code Structure Reorganization:

   • Split the code into three main functions for better modularity: a. hollow_diamond_alphabet: Pattern generation b. get_valid_input: Input handling and validation c. main: Overall program flow control

5. Function Return Values:

   • Modified hollow_diamond_alphabet to return a boolean indicating success or failure.
   • get_valid_input now returns the validated input or None if the user quits.

6. Main Function Addition:

   • Introduced a main function to control the program's flow.
   • Implemented the if __name__ == "__main__": idiom for proper script execution.

7. Improved Readability:

   • Added more comments and docstrings for better code understanding.
   • Improved spacing and formatting for clearer code structure.

These changes make the program more robust, user-friendly, and adherent to good programming practices. The program now handles various edge cases and provides a better interactive experience for the user while maintaining its core functionality of generating hollow diamond patterns with alphabet characters.

• [ ✓] 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:

• [ ✓] I have read CONTRIBUTING.md.
• [✓ ] This pull request is all my work -- I have not plagiarized.
• [✓ ] I know that pull requests will not be merged if they fail the automated tests.
• [ ✓] This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• [✓ ] All new Python files are placed inside an existing directory.
• [✓ ] All filenames are in all lowercase characters with no spaces or dashes.
• [✓ ] All functions and variable names follow Python naming conventions.
• [ ✓] All function parameters and return values are annotated with Python type hints.
• [ ✓] All functions have doctests that pass the automated testing.
• [ ✓] All new algorithms include at least one URL that points to Wikipedia or another similar explanation.
• [✓ ] If this pull request resolves one or more open issues then the description above includes the issue number(s) with a closing keyword: "Fixes #12107 ".