Improve u128 zero removal for case <= UINT64_MAX

Author: mborland

include/boost/decimal/detail/remove_trailing_zeros.hpp

@@ -85,9 +85,15 @@ constexpr auto remove_trailing_zeros(std::uint64_t n) noexcept -> remove_trailin
     return {n, s};
 }
 
-// TODO(mborland): Make this better. Check lower word for equal to 0.
+// TODO(mborland): Make this better for the 2-word case
 constexpr auto remove_trailing_zeros(uint128 n) noexcept -> remove_trailing_zeros_return<uint128>
 {
+    if (n.high == UINT64_C(0))
+    {
+        const auto temp {remove_trailing_zeros(n.low)};
+        return {static_cast<uint128>(temp.trimmed_number), temp.number_of_removed_zeros};
+    }
+
     std::size_t s {};
 
     while (n % 10 == 0)