Improve explicitness of help doc of --command on rez-env

[brycegbrazen]

Felt like this explicit mention of non-interactivity is helpful for users new to Rez.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 58.05%. Comparing base (dc2c777) to head (ee4e056).

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```diff @@ Coverage Diff @@ ## main #1682 +/- ## ======================================= Coverage 58.05% 58.05% ======================================= Files 126 126 Lines 17035 17035 Branches 3490 3490 ======================================= Hits 9889 9889 Misses 6482 6482 Partials 664 664 ```

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[bpabel]

Thanks for your recommendation! I agree it could be better worded. A few things I think could be improved:

• "read" is a poor verb choice; all arguments are read. "execute" would be a better verb.
• denoting it as a "string" is redundant, all commands are strings.
• "command arguments" is misleading; it's actually a full command and command arguments.

Something like "Execute command within rez environment and exit..." would be better, plus your other additions (also, replace "command arguments" with just "command")

Would you mind updating?

[bpabel]

Also, something I just realized, the command and arguments passed to -c must be passed in as a single shell argument, whereas the command and arguments after -- are all passed in as separate shell arguments.

That should probably be noted somehow in the help text.