Minor suggestions to installation docs.

[davidwilby]

Hi folks, just a couple of minor suggestions to the installation docs, feel free to close if wrong or not required!

This pr:

• Adds repo url to git clone command to make more explicit for any new git users - appreciate that this may have been a deliberate choice so feel free to edit or reject.
• Reorders options for editable pip install from pip install -e -v . to pip install -v -e . since the first arg after -e is taken as the install source, meaning the first example fails (at least with pip v 23.3.1),
• Adds a note advising virtual environments, this may just be a personal preference for python project install docs, so can remove if you're not keen.

Thx! This looks like a great project! :rocket:

[tom-andersson]

This is great, thank you for improving the docs @davidwilby!