Building documentation

This chapter describes how to build documentation of toolchain components, either in whole or individually.

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.py doc
```
If you want to be sure the documentation looks the same as on CI:
```
./x.py doc --stage 1
```
First, the compiler and rustdoc get built to make sure everything is okay, and then it documents the files.
Much like running individual tests or building specific components, you can build just the documentation you want:
```
./x.py doc src/doc/book
./x.py doc src/doc/nomicon
./x.py doc compiler library
```
Document internal rustc items

Compiler documentation is not built by default. To enable it, 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.