message: sync: const-qualify the argument of double_lock_detected()
  It is not modified in the function, so should be `const`.
diff: @@ -139,7 +139,7 @@ static void potential_deadlock_detected(const LockPair& mismatch, const LockStac
  throw std::logic_error(strprintf("potential deadlock detected: %s -> %s -> %s", mutex_b, mutex_a, mutex_b));
  }
  -static void double_lock_detected(const void* mutex, LockStack& lock_stack)
  +static void double_lock_detected(const void* mutex, const LockStack& lock_stack)
  {
  LogPrintf("DOUBLE LOCK DETECTED\n");
  LogPrintf("Lock order:\n");
  