- `strict_not_null<std::unique_ptr<int>>{ std::make_unique<int>()}` failed to compile
- `strict_not_null` ctor needs to move the passed `unique_ptr`, not copy
- Copied `not_null` `TestNotNullConstructors` for `strict_not_null`
- The `noexcept` specifiers on the `strict_not_null` and `not_null` constructors were out of sync.
- Added unit test for `not_null<unique_ptr<T>>` and for `strict_not_null<unique_ptr<T>>`
- Added unit test for `gsl::swap` for two `strict_not_null`
- Added unit test for `gsl::swap` for `not_null` and `strict_not_null`
Co-authored-by: Werner Henze <w.henze@avm.de>
