clang-tidy "errors" should not have exclusions applied (and other exclusion-related bugs)

Use

```
#include <vector>

int main()
{
    std::vector<int> vi{};
    vi.emplace_back(std::pair<int, int>{});
}
```

We filter out the clang error (assuming system headers warnings are filtered out)...ideally we'd show it in this case, i.e. when there is a "note" referencing a non-excluded file.