P.CMT.03 Use line comments and avoid block comments

[Description]

Try to use line comments (// or ///) rather than block comments. This is a convention in the Rust community.

For documentation comments, use //! , in other cases /// is better.

Note: #! [doc] and #[doc] have a special role in simplifying document comments, and it is not necessary to force them into //! or //.

[Bad Case]

#![allow(unused)]
fn main() {
// Bad

/*
 * Wait for the main task to return, and set the process error code
 * appropriately.
 */
mod tests {
    //! This module contains tests

    // ...
}
}

[Good Case]

When normalize_comments = true:

#![allow(unused)]
fn main() {
// Good

// Wait for the main task to return, and set the process error code
// appropriately.

// Good
// When defining modules using the `mod` keyword, 
// it is better to use `///` on top of `mod`.

/// This module contains tests
mod tests {
    // ...
}

// Good
#[doc = "Example item documentation"]
pub enum Foo {}
}

【rustfmt configuration】