add python-venv state

[Peter-Chou]

add python-venv state using python-shell-virtualenv-root variable, Any virtual environment manager,e.g. pipenv.el, pyvenv.el, conda.el, which changes this variable can trigger the python-venv state

venv activated in non-pipenv project:

venv deactivated in non-pipenv project:

venv activated in pipenv project:

venv deactivated in pipenv project:

In these demos, I used pyvenv.el instead of pipenv.el to manage the virtual environment

[seagle0128]

Thanks for the PR!

If I understand correctly, you want to add a segment of venv state after major-mode and version. But I don't understand what's the meaning of displaying the directory in mode-line. I took a quick look at the codes of pyvenv. Actually pyvenv-mode-line-indicator will be showed in mode-line-misc-info of mode-line. That makes more sense. doom-modeline supports mode-line-misc-info, so I don't think this segment is necessary.

What's more, the codes will cause some exceptions. I added the comments there.

[Peter-Chou]

You are right, I haven't thought about it.
normally I use the functions in pyvenv-mode without enabling the minor mode and pyvenv-mode-line-indicator won't be shown in modeline if it were used in that way.
It seems this segment is more suitable for the customized usage scenarios.
Thank you for informing me about that 😚

[seagle0128]

If you prefer the standalone segment for pyvenv, should keep it similar as pyvenv-mode-line-indicator or just leverage it. That should be flexible and make sense. Thanks again!