docs/comparisons: Add pae/pactivate

[0cjs]

• I have added a news fragment under changelog.d/ (if the patch affects the end users)

(Does not affect users of the program; documentation update only.)

Summary of changes

Add comparison with a somewhat similar tool, pae/pactivate.

Test plan

Tested by regenerating the documentation with nox -s build_docs and reading the new output in site/comparisons/index.html.

[Gitznik]

Thanks for contributing to the docs :)

[0cjs]

Note that I'm putting up separate commits on the dev branch for each separate conversation here; I believe this should make reviewing easier. I'll of course squash these all into one commit when we're ready to merge, unless you guys think that this history here should be kept.

[0cjs]

I've just added a new bullet point near the top that I think more precisely explains a core difference in approach between pipx and pae. I realise this whole thing may be getting a bit long; I'm open to removing whatever you think isn't too important. (I could also add a section in the pae/pactivate documentation with a detailed comparison with pipx, and we could just summarize here and link to that, if that sounds like a better idea.)

[0cjs]

By the way, I did play with the pipx inejct command to inject other packages into a virtual environment, but it didn't create links in my ~/.local/bin/ for the CLI programs in it. And actually even programs for dependencies don't get links. (I do believe that both these decisions are correct for pipx.) Is there any way with pipx to run an arbitrary program from a specific virtual environment other than giving the full path to it, e.g., ~/.local/share/pipx/venvs/grip/bin/flask --version?

[0cjs]

Ok, I've created a detailed comparison in the pactivate documentation, and slimmed down the one here to cover just the essentials and link to the details. Thoughts?

(As usual, this is a separate commit on the end; a squash will bring the whole set down to just what's on the end.)