Добавить "Mutability"

[ilyakmet]

Rust has many ways to allow some safe mutability inside of something that is immutable. The most simple way is called Cell. First we use use std::cell::Cell so that we can just write Cell instead of std::cell::Cell every time.

[funkill]

Предлагаю внести как вариант к mutable - изменяемый, mutability - изменяемость/изменчивость