To ensure the correct toolchain is used when building and testing the
project, a pre-plan action is added for `rustup`.
It uses the same `channel` as defined in the `rust-toolchain.toml`.
A note is left about this duplication, and the possibility of it being
supported in the future.
Note that this includes a workaround:
```
sed -i /components/d rust-toolchain.toml
```
which ensures that `components` are removed, since Ambient does not
support `components` at this time.
Currently, `cargo doc` fails on warnings for missing links to
`qcheck` and `radicle_git_ref_format`. This will enable the required
features to compile those modules in.
Fintan Halpenny
Erik Kundt
Lars Wirzenius