venv: activate.fish breaks prompt (prints directory) due to "echo 'exit $old_status' | ." line

[atagtm]

Bug report

Bug description:

python3 -m venv test
source test/bin/activate.fish

causes ls-like output on every command.

Fix in venv/scripts/common/activate.fish:

        # Output the original/"old" prompt.
        _old_fish_prompt
        # Restore the return status of the previous command.
       return $old_status

fish, version 4.1.2

CPython versions tested on:

CPython main branch

Operating systems tested on:

Linux