`chezmoi cd` to accept an optional path, cd into the corresponding managed path

[RuijieYu]

Is your feature request related to a problem? Please describe.

Sometimes when I am deep in my configuration files (like ~/.config/zsh/path/to/subconfig/files), I would like to quickly jump to its corresponding source state under ~/.local/share/chezmoi/.... Currently chezmoi cd simply goes to the root of the git repository.

Describe the solution you'd like

$ pwd
~/.config/chezmoi
$ chezmoi cd .
% pwd
~/.local/share/chezmoi/dot_config/chezmoi
% exit
$ chezmoi cd chezmoi.toml
ERROR: not a directory
$ chezmoi cd /dev
ERROR: (outside $HOME?)
$ chezmoi cd ~/not-managed-directory
ERROR: directory not managed

I haven't thought through how symlinks should work, but this should convey the idea.

Describe alternatives you've considered

The alternative would simply be not have this feature and cd to the managed path manually.

[twpayne]

This is a great idea, thank you!