This replaces the `std::get` call with an unqualified equivalent to allow
it to be treated as a dependent call.
ranges.h needs std::get overloads from `<tuple>` but does not directly
include it. This causes compilation failures in MSVC with /permissive-.
On other platforms `<tuple>` is included as a dependency from other headers
(specifically from `<memory>`), but there is no such implicit dependency in
MSVC's STL.
Fixes#2401
889bbf27a2