Update "Foreign Shell Scripts" to mention `source-env`

[xpe]

I think https://www.nushell.sh/cookbook/foreign_shell_scripts.html might be stale. Shouldn't it mention source-env?

I'm new to nushell, so I don't know the history.

[xpe]

Gemini 2.5 Pro, right or wrong, says:

The discrepancy you've found highlights the rapid evolution of Nushell. What you're seeing is a snapshot of a problem and its solution from an earlier point in time.

The Old, Manual Method (The bash-env-plugin Era)

In earlier versions of Nushell, there was no direct command for this common task. The "Working with Foreign Shell Scripts" page documents the advanced, do-it-yourself solutions of that time: either manually parsing strings or, as you found, writing and compiling a custom plugin to act as a bridge to Bash. This was powerful but cumbersome.

The Modern, Built-in Solution (source-env)

The Nushell developers rightly identified this as a major friction point. They took the core logic of these manual methods and baked it directly into the shell as the source-env command. This command was stabilized around version 0.78 (released in early 2023) and is now the official, idiomatic way to solve this problem.

The cookbook page is therefore an artifact of a time before source-env existed.