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

[jfeingold35]

Closing and reopening the PR so the CLA updates.

[jfeingold35]

@khaled4vokalz , I'm unable to QA this locally with my own plugins, for some reason. Do you have an example of a plugin with aliased flags that will now work properly because of this PR?

[khaled-maruf]

@jfeingold35 ,
Sorry, I'm on vacation currently, so not looking at github that much, I'll try to share something that I tested this with...

[khaled-maruf]

@jfeingold35 ,
Wait but it's about the flag aliases for the cli commands, so you can just add some commands with some flag aliases and use yalc to use this version of the plugin-autocomplete in the package.json of that CLI and test the autocompletes.