fix: for clang-tidy include-cleaner check

[Neptunium931]

Using criterion and clang-tidy with check misc-include-cleaner is not possible because criterion uses an umbrella-headers see: include-cleaner#umbrella-headers clang-tidy makes the following change:

-#include <criterion/criterion.h>
+#include <criterion/internal/test.h>
+#include <criterion/internal/assert.h>

Adding // IWYU pragma: private, include "criterion/criterion.h" in to the private header resolves the problem.