Remove first parameter to Run

[azimux]

What's the Change?

This removes the first parameter to Run. It's redundant with a misleading name so this reduces confusion. This was extracted from the "--" PR to make that simpler but wanted to open a PR with that commit for re-consideration in isolation from the other changes.

The command parameter doesn't actually represent a command. A more descriptive name would be something like working_directory_or_entry_point_or_switch_of_first_cli_option though obviously too long so a shorter name for that would be something like first_arg. The argv parameter already contains this along with other args. Exposing this through Run's public interface imposes this confusion on the calling code such that it has to know to always pass the first argv as both the first parameter to Run as well as the first element of the second parameter to Run otherwise things don't work. And calling it command instead of first_arg increases the confusion.

Checklist

• Added tests

^ Technically just updated existing tests that were added in the PR this was extracted from

• Added documentation
• Updated migrations/0_4_to_0_5.md if it's a breaking change
• Added an entry to changelog.md

^ Seems like for an internal interface change like this there's probably not much value of adding it to the changelog but can if desired of course.

• Run dx/exec bundle exec rake ci

^ running this command locally doesn't seem to do anything useful.

[azimux]

This also shows the confusion. It's a strange interface/contract to tell the calling code "whatever is the first argv, you must also passed as the first argument." As mentioned, there's never a command in this position, either. It's just an arbitrary requirement to duplicate the data there. This also happens in other tests below.

[azimux]

Same thing here. It's a confusing interface to be required to pass "--" twice, both times representing an argv entry, and not representing a command at all.