Rust comes with extensive documentation. For example:

In fact, you can document your own code:

/// Determine whether the first argument is divisible by the second argument.
/// If the second argument is zero, the result is false.
fn is_divisible_by(lhs: u32, rhs: u32) -> bool {
    if rhs == 0 {
        return false;
    lhs % rhs == 0

The contents are treated as Markdown. All published Rust library crates are automatically documented at using the rustdoc tool. It is idiomatic to document all public items in an API using this pattern.

To document an item from inside the item (such as inside a module), use //! or /*! .. */, called “inner doc comments”:

//! This module contains functionality relating to divisibility of integers.
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