Fix BinaryName initialization from args

[petrem]

Fixes an issue with completion bash where the command name is not present in the completion output.

[github-actions]

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[iHiD]

Forum discussion: https://forum.exercism.org/t/exercism-completion-bash-not-working/13100/2

(cc @exercism/cli)

[glennj]

Don't know go all that well. This looks reasonable.

[iHiD]

@ErikSchierboom Are you ok to merge/release this when you're back around pls?