[rust] link to, incorporate, or track other rust guides?

[g-k]

specifically:

• https://github.com/ANSSI-FR/rust-guide

and for unsafe:

• https://github.com/rust-lang/unsafe-code-guidelines
• https://doc.rust-lang.org/nightly/nomicon/working-with-unsafe.html

[g-k]

https://github.com/rust-unofficial/patterns