This makes it easier to launch Signet and testnet4 on Windows. Follows the same pattern as testnet.
Before:
<img width="766" alt="testnet" src="https://user-images.githubusercontent.com/10217/196468934-ee29d129-871b-4612-bde4-842f191403a7.png">
After: <img width="500" alt="signet1" src="https://user-images.githubusercontent.com/10217/220358057-d9efc532-272c-45e7-81fa-3a52f58a0f29.png"> <img width="527" alt="signet2" src="https://user-images.githubusercontent.com/10217/220358067-62b3b76f-604a-4163-9d35-c903fff29df0.png">
(the testnet4 icon is the same as testnet3, not in the above screenshot)
