Suppress some annoying lints in what way

[qryxip]

BTW, how do we suppress clippy::many_single_char_names? Adding #![allow] to each module, or the crate root?

#![allow(clippy::many_single_char_names)]

Originally posted by @qryxip in https://github.com/rust-lang-ja/ac-library-rs/pull/3#issuecomment-688622868

[qryxip]

I prefer adding to each module/item or avoid single-character variable names in the first place, but adding to lib.rs is a reasonable approach since many_single_char_names gets easily triggered.

[qryxip]

CC: @TonalidadeHidrica @koba-e964 @kenkoooo

[kenkoooo]

I think many_single_char_name warning is still useful. I know AtCoder's library is using a lot of single-character variables. To avoid confusing the library users, it's better not to change the behavior and the interface. But we can change the variable names. It will help reviewers read the code and find bugs and help users understand the algorithms.

[qryxip]

note: Clippy is currently bundled with rustup (if you newly install Rust, you'll also install cargo-clippy), and be intended to used as a static code analysis tool running on editors such as VSCode.