Problem description

This is another attempt after #3567, also related to #3517.

I'm pretty sure than my students and co-workers not used to Pixi won't remember pixi shell --manifest-path ..., in particular because they don't know (and don't need to know) the meaning of a Pixi manifest file, and also because we actually need pixi shell --manifest-path /path/of/a/directory (they won't even need to know that there is a manifest file in this directory).

However, it would be very useful for them to be able to run such command.

Moreover, --manifest-path is very long for a command that you need to write quite often.

Therefore, I was wondering if it could be possible to add a one-letter alias to --manifest-path, for example -p (like "project" and "path", so easy to remember)?

PS: the same reasoning applies for pixi run --manifest-path...