Improve docs: Installation & updating

This is a question about how the pyenv-win works and also suggestion to add, if needed, some comments to the documentation.

Are the following statements true?

1. pyenv-win installed with pip (C:\<some-python>\Scripts\pip.exe) can only be updated using the same pip (C:\<some-python>\Scripts\pip.exe).
2. pyenv-win installed with git can only be updated using git.
3. pyenv-win installed with Chocolatey can only be updated using Chocolatey.

If 1. is true, what happens if the C:\<some-python> gets removed from the system? Can you update pyenv-win at all?

If any of 1., 2., or 3. is true, it could be very handy to include in the documentation, to the "Installation" section some sort of comment that says "NOTE: Your installation method determines on how you can/must update the pyenv-win in the future".