Plus the count of [`Iterator::enumerate`] by `base`
# Example
```rust
use crate::enumerate_base::EnumerateBaseExt as _;
let arr = ['a', 'b', 'c', 'd'];
let iter = arr.into_iter().enumerate().base(2);
assert_eq!(iter.collect::<Vec<_>>(), vec![
(2, 'a'),
(3, 'b'),
(4, 'c'),
(5, 'd'),
]);
```