Common Issues, Fixes & Tips is not very accessible.

Possibly relating to #470: The issues and fixes are a bit obscure thanks to being hidden away.
They are referred to where relevant, but e.g. [here](https://carpentries-incubator.github.io/python-intermediate-development/12-virtual-environments.html#making-sure-you-can-invoke-python) it's at the end of a wordy sentence.

It could potentially be foregrounded more by having the Prerequisite just be the "What you need to be able to do", followed by another large "Common Issues" callout that says (more concisely) "If [problem], check the Common Fixes page" and links to it. Shifting the description of the fix to the fixes section would save enough space that it wouldn't take any extra.