feat: add flag aliases support to autocomplete completions

[khaled4vokalz]

What

Flag definitions can include an aliases array property that allows alternative names for the same flag (e.g., --no-progress and --noProgress). Previously, only the primary flag name was included in generated autocomplete scripts.

This change ensures flag aliases are included in the completion output for all supported shells:

• zsh: aliases added to _arguments block
• bash: aliases added to the commands list
• powershell: aliases added to the flags hashtable

Example output from a dummy cli:

$ my-cli app result -<TAB>
--bump-dev-version     --bumpDevVersion           -- Bump dev version before building.
--help                                            -- Show help for command
--no-progress          --noProgress               -- Don't display any progress indicators
--path                 -p                         -- The root directory of the app

Closes #1088

[salesforce-cla]

Thanks for the contribution! Before we can merge this, we need @khaled4vokalz to sign the Salesforce Inc. Contributor License Agreement.

[khaled4vokalz]

Thanks for the contribution! Before we can merge this, we need @khaled4vokalz to sign the Salesforce Inc. Contributor License Agreement.

done

[khaled4vokalz]

@cristiand391 , any plans with this? Sorry for the push, but It'd be really helpful for some of our use-case we're using oclif for...

[sergei-dyshel]

This CR duplicates some code and also doesn't take charAliases into account.
I prototyped a simpler solution here sergei-dyshel@7166e9b