Document enabling `gh-pages` and `.nojekyll` about ghaction-github-pages

[kousu]

Ah okay you do document

jekyll Bool Allow Jekyll to build your site (default true)

But this is kind of confusingly worded. Why would you want to use this Action if you weren't trying to use a different static site generator than jekyll?

Having this enabled by default causes Github to 404 all accesses to files in folders named with leading _s, which is unfortunate because sphinx uses those heavily: _static/, _images/ and _sources are in every build it does.

[crazy-max]

But this is kind of confusingly worded. Why would you want to use this Action if you weren't trying to use a different static site generator than jekyll?

This is enabled by default because that's the default behavior of GitHub Pages when an event occurs on the gh-pages branch as you found out in https://docs.github.com/en/pages/getting-started-with-github-pages/about-github-pages#static-site-generators

So when the action push content on your GitHub Pages branch a GitHub bot will trigger an internal workflow that will look like this:

As you can see in https://github.com/crazy-max/ghaction-github-pages/runs/4773640592?check_suite_focus=true, this workflow will pull a jekyll image to build the website on that branch because there is no .nojekyll file available on this branch:

If you add a .nojekyll it will be a simple deployment. See https://github.com/crazy-max/crazy-max.github.io/runs/4786879422?check_suite_focus=true