Missing deprecation of old device selector interface

[mkinsner]

SYCL 2020 added a new callable device selector, and contains the non-normative note:

In SYCL 1.2.1 the predefined device selectors were actually types that had to be instantiated to be used. Now they are just instances. To simplify porting code using the old type instantiations, a backward-compatible API is still provided, such as sycl::default_selector. The new predefined device selectors have their new names appended with "_v" to avoid conflicts, thus following the naming style used by traits in the C++ standard library. There is no requirement for the implementation to have for example sycl::gpu_selector_v being an instance of sycl::gpu_selector.

Since there is a new form, and the old form isn't actually defined in SYCL2020, it seems odd that the old form hasn't been marked as deprecated. Is there a reason for lack of deprecation, or is this a spec bug?

[tomdeakin]

22/11/24: likely missing the deprecation as SYCL 2020 clarification. Please prepare PR.