fix: prepare for potential future changes in drv output selection fragment

[blaggacao]

Context

On newer version of Nix (e.g. 2.16), this warning hints the user on potential upcoming changes:

warning: The interpretation of store paths arguments ending in `.drv` recently changed. If this command is now failing try again with '[ ... ].drv^*'

Solution

This PR implements the suggestion of the warning message verbatim.

[blaggacao]

assuming we consider nix v2.13 incompatible

Oh thanks for bringing this up. I hadn't considered this.

We could & probably should, meaning that while Paisano requires 2.10.3, Standard exceeds that and requires 2.13.

Will prep a fix.

[blaggacao]

Tested and confirmed to implement the desired effect.