Improving documentation

Created by: timrossback

Hey,

I'm looking through the contributing guidelines, and I've noticed that it directs future-contributors to edit documentation on the master branch, under the /bootstrap/docs/ directory.

Similarly, when contributing to Bootstrap's documentation, you should edit the documentation source files in the /bootstrap/docs/ directory of the master branch. Do not edit the gh-pages branch. That branch is generated from the documentation source files and is managed separately by the Bootstrap Core Team.

However:

1. There is no /bootstrap directory (there is a /docs though)
2. The documentation in /docs/_includes hasn't been updated in ~2 years (apart from #23808)

So, should where should I be targeting my PRs against?