no need to strip accumulator twice

mishmash.cpp

             accumulator += accumulator >> 32;
             accumulator &= 0x00000fffffffffff;
         }
-        return accumulator & 0x00000000ffffffff;
+        return static_cast<uint32_t>(accumulator);
     }
 
     uint32_t mishmash(const std::string& s) noexcept {