Building documentation

This chapter describes how to build documentation of toolchain components, like the standard library (std) or the compiler (rustc).

Document everything

This uses rustdoc from the beta toolchain, so will produce (slightly) different output to stage 1 rustdoc, as rustdoc is under active development:
```
./x doc
```
If you want to be sure the documentation looks the same as on CI:
```
./x doc --stage 1
```
This ensures that (current) rustdoc gets built, then that is used to document the components.
Much like running individual tests or building specific components, you can build just the documentation you want:
```
./x doc src/doc/book
./x doc src/doc/nomicon
./x doc compiler library
```
See the nightly docs index page for a full list of books.
Document internal rustc items

Compiler documentation is not built by default. To create it by default with x doc, modify config.toml:
```
[build]
compiler-docs = true
```
Note that when enabled, documentation for internal compiler items will also be built.

NOTE: The documentation for the compiler is found at this link.