Function next_steps_message 

pub fn next_steps_message(shell: Shell, rc_path: Option<&Path>) -> String

“What to do next” blurb shown after runex init finishes. The integration line lives in the rcfile but the currently-running shell hasn’t sourced it yet, so the user has to either reload the rcfile or open a fresh shell. Each shell has its own idiomatic reload command; clink keeps no rcfile and just needs a new cmd.

rc_path is the file we just appended to (or None for clink, where the integration goes into a separate lua file rather than an rcfile).