pkgs/by-name/README: explicitly suggest version specific override interfaces

The current advice of "keeping the override interface" is actively bad,
because it hides certain expectations of a package function in an
undiscoverable place. Ideally, all information about a package is in
one, single place instead.

Version-specific argument names, if required, also have the *benefit* of
creating errors with downstream overrides, much like merge conflicts do.
Instead of possibly silently breaking certain behavior, they make a
change in expectations clear - which might feel annoying when upgrading,
but is ultimately much less problematic down the road.

0 files changed, 0 insertions, 0 deletions