fix: Prepend asdf directories to the PATH in Nushell

[etoal83]

Summary

In the Nushell setup script, I change the paths to asdf shims and bin to be prepended in front of the existing $PATH instead of being appended at the end. This change makes asdf plugins have priority over the existing commands in the search path as well as other shells' setup.

[jthegedus]

All our Shell integrations use append due to significant user feedback when changing this to prepend in the past. I think we should stick with append.

What is the specific use case troubling you that requires this?

[Stratus3D]

@jthegedus it appears we prepend to the asdf paths to $PATH in asdf.sh. It appears the changes here from @etoal83 make Nushell consistent with Bash/Zsh in this regard. I am in favor of this change if I'm understanding things correctly.

To me it also seems easier to reason about a script that adds something to the beginning of the $PATH. When you source it in your .zshrc/.bashrc you be certain that asdf is added at the beginning of $PATH, anything that comes before it in the rc file ends up after asdf on PATH, and anything after it in the rc file comes before it on the PATH.

[etoal83]

@jthegedus @Stratus3D

Thank you for commenting! What I intended with this PR is correctly explained by @Stratus3D .

What is the specific use case troubling you that requires this?

Appending the path becomes a problem when the same command already exists in the user environment. Because the current asdf.nu appends the $shims_dir and $asdf_bin_dir paths to the existing $PATH, a preinstalled version of executable was used in the command over the asdf version. I think in most situations people installing asdf would prefer to use the asdf version of the executable rather than the existing one.

This PR changes the asdf path setting from/to:

• before: $PATH:$shims_dir:$asdf_bin_dir
• after: $asdf_bin_dir:$shims_dir:$PATH

Sorry if the use of my word "append" and "prepend" were misleading😣

[jthegedus]

Sorry for the confusion, I misunderstood the current state. I should have validated 😅