[Bug c++/113153] suboptimal error message when using reserved identifier

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113153

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
If you remove the class, GCC has a decent error message:
```
<source>:1:11: error: expected identifier before 'register'
    1 |     enum  register { rax, rcx, rdx, rbx };
      |           ^~~~~~~~
```