Change GitHub Pages branch recommendation to put docs in same branch as code

[benlk]

Is your enhancement related to a problem? Please describe.
The GitHub Process docs section Documentation reads:

Depending on the amount of documentation associated with your projects usage instructions, you may find that hosting them as a separate view, such as GitHub Pages or a GitHub wiki, is preferable to markdown files in a /docs/ subfolder. Note that if you go the GitHub Pages route, that you’ll want to consider a gh-pages branch that deploys to your GitHub Pages site.

Since 2020-07-31, GitHub now supports having GitHub pages build from a maintainer-specified branch, and from a specific folder within the repo. Using this option would allow GH Pages docs to be version-controlled alongside the source code they document, so that the docs and repo

Describe the solution you'd like

Something like:

Depending on the amount of documentation associated with your project's usage instructions, you may find that hosting them in a separate view, such as GitHub Pages or a GitHub wiki, is preferable to markdown files in a /docs/ subfolder.

If you go the GitHub pages route, you should:

• create the GitHub Pages root within a folder in the repository such as /docs/, and configure GitHub Pages to build from that folder.
• update the documentation when the corresponding code is updated.
• configure GitHub Pages to build from the branch of the project that represents the version of the code users will encounter if they are using an up-to-date version of the project. This would be a release, stable, or trunk branch, instead of a develop or gh-pages branch.

In this way, merging a feature or development branch that contains new/updated code will simultaneously update the documentation to match the new code.

Describe alternatives you've considered

Alternatives include our present recommendations for best practices.

Additional context

GitHub added the ability to build and deploy GitHub pages from any branch on July 31, 2020.

This issue follows from #62

[jeffpaul]

The suggested update seems good to me. @helen you 👍🏼 on this update?

[jeffpaul]

@benlk want to handle a PR to make these changes?