unnecessary numerics when handling two or more unknown modes

```
>>> MODE #ccc +XY
:testnet.ergo.chat 472 ccc X :is an unknown mode character to me
:testnet.ergo.chat 472 ccc Y :is an unknown mode character to me
:testnet.ergo.chat 324 ccc #ccc +nt
:testnet.ergo.chat 329 ccc #ccc 1738636568
```

324 and 329 are unnecessary here, the condition is just slightly wrong.