Comparison operators for range and id don't return bool

The comparison operators (`<`, `>`, `<=`, `>=`) for `range` are defined in [4.9.1.1](https://registry.khronos.org/SYCL/specs/sycl-2020/html/sycl-2020.html#range-class) as:
```c++
// OP is: +, -, *, /, %, <<, >>, &, |, ^, &&, ||, <, >, <=, >=
friend range operatorOP(const size_t& lhs, const range& rhs) { /* ... */
}
```

The equivalent operators for `id` are similarly defined in [4.9.1.3](https://registry.khronos.org/SYCL/specs/sycl-2020/html/sycl-2020.html#range-class) as:
```c++
// OP is: +, -, *, /, %, <<, >>, &, |, ^, &&, ||, <, >, <=, >=
friend id operatorOP(const id& lhs, const id& rhs) { /* ... */
}
friend id operatorOP(const id& lhs, const size_t& rhs) { /* ... */
}
```

I find this behavior confusing. I understand that imposing a strict ordering on these multi-dimensional objects doesn't make a lot of sense, which makes it impossible to return a `bool` in general. But in the 1-dimensional case we _could_ return a `bool`, and in the multi-dimensional case a developer will always have to loop through the resulting range (so it's unclear if this operator would actually make their code any simpler).

Is there a use-case for the multi-dimensional comparisons? It seems like only allowing comparisons for the one-dimensional cases would be simpler.

Start with SYCL specification sections 4.9.1.1 and 4.9.1.3, linked in the issue, and review the 20-comment discussion for an agreed direction. Determine whether the range and id comparison operators should be changed or clarified; done means a decided specification change or an explicit rationale for retaining the current behavior.

Written by the indexing model from the issue text.