Provide `ensurepath` with a check option or create an `init` command

How would this feature be useful?

Currently, pipx ensurepath does not tell me what changes will it make. I would like to stay in control: see what changes it would make, and then decide if it's okay with me.

Describe the solution you'd like

• Add a --check or --dry-run option that checks for necessary changes and outputs them.

  > pipx ensurepath --dry-run
  # append lines to ~/.config/fish/config.fish
  fish_add_path ~/.local/bin
  # ... and other configs
  

Describe alternatives you've considered

• Add an init command that outputs the shell config changes - similarly to how pyenv does it:

  > pipx init --fish
  # Add this to your config.fish file if You haven't yet
  fish_add_path ~/.local/bin
  # ... other configs - similarly --zsh or --bash or --tcsh
  

Here is how pyenv does it:

> pyenv init
# Add pyenv executable to PATH by running
# the following interactively:

set -Ux PYENV_ROOT $HOME/.pyenv
set -U fish_user_paths $PYENV_ROOT/bin $fish_user_paths

# Load pyenv automatically by appending
# the following to ~/.config/fish/config.fish:

pyenv init - | source


# Restart your shell for the changes to take effect.