modint<>: Add an line break at the end

It would be easy to copy.

Author: xirc

lib/cpalgo/util/modint.hpp

@@ -62,4 +62,4 @@ class modint {
     constexpr bool operator==(modint const& rhs) const noexcept { return x == rhs.value(); }
     constexpr bool operator!=(modint const& rhs) const noexcept { return !(*this == rhs); }
     friend constexpr std::ostream& operator<<(std::ostream& os, const modint& x) noexcept { return os << x.value(); }
-};
+};