Missing impls when using nom 8 with `bits`

[jgeibel-burns]

In #1747 the InputLength trait was removed and all bounds were transitioned over to Input. However, Input is only implemented for &[u8] and &str whereas InputLength was also implemented for (&[u8], usize), [u8; N], &[u8; N], and &[T] (for any T, not just u8).

In particular, the loss of the (&[u8], usize) implementation seems to have broken many combinators when used with items under nom::bits. In my attempt to port to nom 8, I'm running into issues with combinator::eof and multi::many_till though I expect users would run into issues using any of the functions with modified bounds under those 2 modules. (I'm not currently using anything under bytes or character so the impacts there, and due to the other dropped impls, is less clear to me.)

Here is a reduced test case that compiles for me with nom 7 but not nom 8:

use nom::bits::bits;
use nom::combinator::eof;
use nom::error::Error;
use nom::{IResult, Parser as _};

fn main() {
    let _ = test(b"");
}

fn test(bytes: &[u8]) -> IResult<&[u8], ()> {
    bits::<_, _, Error<(&[u8], usize)>, _, _>(eof)
        .map(|_| ())
        .parse(bytes)
}