Docs for path expressions are too hard to find

[lutter]

To find them, you need to know to look on the Wiki; to make matters worse, there are quite a few places where a broken link goes to a nonexistent page (e.g., in http://augeas.net/docs/tree.html)

[hillu]

Is the documentation on http://augeas.net/ unmaintained at this point?

[lutter]

"Unmaintained" is probably too strong a word, but it could definitely use some TLC. What I would love to have is one central place where all documentation sources live in git, ideally in the doc/ directory in this repo, organized in such a way that it is easy to generate a book-like artifact, e.g. with gitbook. The current state of having them scattered in various places, and not well organized, is unsatisfactory.