Fix attribute ordering

[lucashecht]

When trying to build the hypervisor I got the following error:

main.cpp:118:5: error: an attribute list cannot appear here
  118 |     [[nodiscard]] extern "C" auto
      |     ^~~~~~~~~~~~~

Apparently putting an attribute list before extern "C" doesn't conform to the C++ standard and clang has stopped allowing this at some point: https://reviews.llvm.org/D126061

This pr fixes the two declarations where the wrong order was used.