complete doas commands

[ghost]

so that a command completes when prefixed by doas, like this doas command

This is not for completing doas it self.

it seams there's was confusion:
#837 was about to do the same thing, but they thought that it was a duplicate of #766 but that's for doas it self.

[akinomyoga]

#766 but that's for doas it self.

#766 is a superset of #837 and this PR. The feature #837 and this PR try to add is supposed to be provided by #766 on this line.

@exponentialmatrix If you don't think so, could you please explain it?

[ghost]

I don't understand the complexities of bash completion, i saw all the sudo like stuff there, i added doas and it started working.
766 is there for 3 years and it seams it will never be merged.

It seams that the line of this PR adds support for sudo like apps without a dedicated profile. In that sense it's correct.

I'm proposing to merge this one and add a correcting commit to 766 for when it will be merged.

[akinomyoga]

The main reason that #766 is not merged is not because it is more complicated. It's pending because there is no action or response about the confirmation with the upstream as requested in CONTRIBUTING.md. This PR #1423 has the same issue.