A new Visual Studio version will soon be available that deprecates the
old syntax for gsl::suppress. Customers will now get a C4875 diagnostic
on suppressions that look like `gsl::suppress(x)` urging them to use
`gsl::suppress("x")` instead.
This change updates the `GSL_SUPPRESS` macro to preprocess
GSL_SUPPRESS(x) to gsl::suppress("x") on clang and new versions of MSVC.
* move span specialization of 'at' to <gsl/span> and update the parameter to be taken by reference
* undid previous changes and acted upon decisions made in maintainer sync. Fixed tests failing in /kernel mode
* ran clang-format on the include folder
* ran clang-format on the test folder
Co-authored-by: Jordan Maples <jordan.maples@microsoft.com>
