sized_range
ranges::size
* adds `sized_range` and conformance tests * moves `disable_sized_range` into namespace `std::ranges` * removes explicit type parameter Implements part of P0896 'The One Ranges Proposal'. Differential Revision: https://reviews.llvm.org/D102434
Based on D101079. Differential Revision: https://reviews.llvm.org/D101189
The begining of [range.prim]. Differential Revision: https://reviews.llvm.org/D101079