Make completions work with an alias

[kurtbuilds]

Right now if you use the README recommended alias, alias j=just, in bash, it stops shell completion from working.

This is a small PR to allow the bash completions script to work with an alias, and adds instructions in the README for how to use it.

[casey]

Thanks for the PR! The completions are actually generated by clap, the command-line parsing library that just uses. I think this should actually be submitted as a PR to the upstream project.

For now though, the changes need to be added to the BASH_COMPLETION_REPLACEMENTS here. It takes the form of a slice of tuples, with the first element being the part to look for, and the second being the part to replace.

[kurtbuilds]

Thank you for the comments! I fixed this PR and added an upstream PR to clap to fix it for other projects.

Note that just still relies on clap version 2.33.3, and I submitted the PR to the master branch, which has version 3.0.0-beta5, so after that PR merges, this PR still should remain until just updates clap to ^3.

I confirmed that the checked-in completions.bash file does not change when re-running completions with the updated completion function included in this PR.

[casey]

Nice, one comment, but otherwise looks great.

[kurtbuilds]

@casey Wanted to make sure this doesn't get lost in the ether - anything blocking merging this in?

[casey]

Thanks for pinging this issue! I didn't get a notification when you made the change to this branch, but it looks good to go. I hit the auto-merge button so it should merge when the tests pass.

[casey]

The tests failed, it looks like because there's a formatting diff.

[kurtbuilds]

Oops, thanks. I ran tests but not formatting. Fixed. It looks like me pushing that caused the auto-merge to reset.

Thank you!