refactor(mkdir): Simplify mode argument parsing

[amirhosseinghanipour]

This pull request refactors the argument parsing for the mkdir utility on the --mode (-m) option.

What does this PR do?

Previously, the utility relied on a manual function (strip_minus_from_mode) to process mode values that begin with a hyphen (e.g., -rwx). This required manipulating the raw argument list before it was parsed by clap.

This change removes the manual parsing logic and uses clap's built-in .allow_hyphen_values(true) setting instead. This approach is cleaner, more robust, and relies directly on the features of the argument parsing library.

Changes made:

• Removed the strip_minus_from_mode function and its related logic.
• Updated the clap argument for --mode to use .allow_hyphen_values(true).
• Refined the uumain and get_mode functions by removing the now-unnecessary variables and parameters.

How to test

I have manually tested the changes to ensure that creating directories with and without a mode flag works as expected. The following commands were used for verification:

# Test basic creation
cargo run -- test_dir

# Test symbolic mode
cargo run -- -m a=rwx test_symbolic

# Test symbolic mode with a leading hyphen
cargo run -- -m -rwx test_hyphen

# Test combined with verbose flag
cargo run -- -v -m a=rwx test_verbose

All commands behaved as expected.

[github-actions]

GNU testsuite comparison:

Skipping an intermittent issue tests/misc/tee (passes in this run but fails in the 'main' branch)
Skipping an intermittent issue tests/timeout/timeout (passes in this run but fails in the 'main' branch)

[sylvestre]

i do get the value of LLM-based coding but please remove the useless comments that your AI wrote...

[amirhosseinghanipour]

Thank you so much for the review and the feedback, Sylvestre! I really appreciate you taking the time. Speaking of comments and AI, this is one of my first open-source contributions, so I'm still learning the project's standards and finding the right balance. I removed them and updated the PR. Thanks again for the guidance. I can't wait to learn from you all! Also, I see my branch has a merge conflict with main now. Just wanted to check in before I force-push the changes. Please let me know if that works for you!

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/timeout/timeout (fails in this run but passes in the 'main' branch)

[RenjiSann]

Thanks !

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/misc/tee (fails in this run but passes in the 'main' branch)
Skip an intermittent issue tests/timeout/timeout (fails in this run but passes in the 'main' branch)