fix broken bash completion

[lyra95]

(If this PR fixes a github issue, please add Fixes #<xyz>.)

Fixes #138.

Works in my local

Motivation

Explain here the context, and why you're making that change. What is the problem you're trying to solve.

bash completion is broken

Modifications

Describe the modifications you've done.

use GenBashCompletionV2 instead of the old one

Verifying this change

• [ ] Make sure that the change passes the CI checks.

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This change is a trivial rework / code cleanup without any test coverage.

Documentation

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Need to update docs?

• [ ] doc-required

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• [x] no-need-doc

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• [ ] doc

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[github-actions[bot]]

@lyra95:Thanks for your contribution. For this PR, do we need to update docs? (The PR template contains info about doc, which helps others know more about the changes. Can you provide doc-related info in this and future PR descriptions? Thanks)

[github-actions[bot]]

@lyra95:Thanks for providing doc info!