This is a squash of the following commits:
- Fix code, remove WIP message as that was while writing this, and link to stable @ fixed 1.49 rather than latest nightly
- Improve wording on deref and ignore some code blocks
- Improve wording and formatting a bit cause I'm insane
- Fix links
- Fix links again because we all love relative links
- Remove unnecessary Drop import
- Use Box::from_raw instead of ptr::drop_in_place as that actually dealloc's the Box (i'm dumb and misinterpreted the std code :/); fix some desync between code in between sections
- Fix tests
mdbook has a lot of optional dependencies that we don't want, so instead
of using it directly, we re-build rustbook to use mdbook as a library.
For convenience' sake, we keep the same CLI interface as mdbook; the
only difference is that it only accepts build and test subcommands,
rather than the full range.