`support/proptest`: Would be nice to have a value range as parameter

*On 2022-05-28 @recmo wrote in [`1ec2e50`](https://github.com/recmo/uint/commit/1ec2e50003548890260e8c06886f44fd826bc07b) “Recognize new tags”:*

Would be nice to have a value range as parameter
and/or a choice between uniform and 'exponential' distribution.

```rust
num::u64::Any,
strategy::{BoxedStrategy, Strategy},
};

impl Arbitrary for Uint {
// FEATURE: Would be nice to have a value range as parameter
// and/or a choice between uniform and 'exponential' distribution.
type Parameters = ();
type Strategy = BoxedStrategy;

fn arbitrary_with(_: Self::Parameters) -> BoxedStrategy {
// OPT: Copy [`UniformArrayStrategy`] to avoid heap allocations

```
*From [`src/support/proptest.rs:11`](https://github.com/recmo/uint/blob/1ec2e50003548890260e8c06886f44fd826bc07b/src/support/proptest.rs#L11)*