`modular`: Modular wrapper class, like Wrapping.

*On 2022-06-03 @recmo wrote in [`2f6a5d6`](https://github.com/recmo/uint/commit/2f6a5d6b21bed46723e8815a63a1724187aa59b1) “Merge pull request #103 from recmo/mulmod”:*

Modular wrapper class, like Wrapping.

```rust
use crate::{algorithms, nlimbs, Uint};

// FEATURE: sub_mod, neg_mod, inv_mod, div_mod, root_mod
// FEATURE: mul_mod_redc
// FEATURE: Modular wrapper class, like Wrapping.

impl Uint {
#[allow(clippy::doc_markdown)] // False positive
/// ⚠️ Compute $\mod{\mathtt{self}}_{\mathtt{modulus}}$.
///

```
*From [`src/modular.rs:5`](https://github.com/recmo/uint/blob/2f6a5d6b21bed46723e8815a63a1724187aa59b1/src/modular.rs#L5)*