improve and fix descriptions of commands

                   
|Q            |A  |
|---          |---|
|Bug Fix?     |n  |
|New Feature? |n  |
|BC Breaks?   |n  |
|Deprecations?|n  |
|Tests Pass?  |n  |
|Fixed Tickets|   |
|License      |MIT|
|Doc PR       |   |
                   


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I think that this is probably OK. I just want to make sure I know what is going on here. Also, I had `app` in there because I didn't want to imply these were `composer` commands. Is there a similar thing to `{$fullCommand}` that shows the command being called? (So for example, sculpin would be able to output "sculpin update vendor/package1 ...")