This pulls all of our long-form documentation into a single document,
nicknamed "the book" and formally titled "The Rust Programming
Language."
A few things motivated this change:
* People knew of The Guide, but not the individual Guides. This merges
them together, helping discoverability.
* You can get all of Rust's longform documentation in one place, which
is nice.
* We now have rustbook in-tree, which can generate this kind of
documentation. While its style is basic, the general idea is much
better: a table of contents on the left-hand side.
* Rather than a almost 10,000-line guide.md, there are now smaller files
per section.
The Windows-specific instruction under 'Quick Start' linked the wiki article on getting started developing Rust itself, but the quick start is just about obtaining a working Rust installation. The actual wiki page with Windows-specific instructions was difficult to find.
The most important thing to note on Windows is that you need mingw-builds, and it is totally not obvious. The only place where I have seen it mentioned is the wiki page, which was difficult to find before.
The Windows-specific instruction under 'Quick Start' linked the wiki article on getting started developing Rust itself, but the quick start is just about obtaining a working Rust installation. The actual wiki page with Windows-specific instructions was difficult to find.
The Guide isn't 100% perfect, but it's basically complete. It's
certainly better than the tutorial is. Time to start pointing more
people its way.
I also just made it consistent to call all things 'guides' rather than
tutorials.
Fixes#9874. This is the big one.
And two bugs that just go away.
Fixes#14503.
Fixes#15009.
Update the instructions to reflect that we have binary installers for all
supported platforms, and move the building from source directions into a
dedicated "Building from Source" directory.
