This was removed in #340510, as the previous implementation didn't work well.
However, it's still the method that's recommended in the patch for the
`llm install` command (`001-disable-install-uninstall-commands.patch`)
and with the additions to `enable` overrides on the top-level `llm`
derivation, there's a need for a place where the LLM plugin "directory"
is specified.
So, I've reintroduced the method with a completely new implementation.
I've also given it some protections against the list of names getting
out of date.
This might be a little too clever, but I think the user-facing interface
for this function is now quite nice.
Philip Taron
0d50348b51