I agree that's an unfortunate omission. The ~ indicates the pins with PWM (analogWrite()) support.
The Nano Every is designed to be compatible with the classic Nano's pinout. The classic Nano had the reset pins there, so the Every must also.
As for why that was done on the Nano, there's an awesome explanation by Juraj here:
Pretty cool to think that the design lineage for the latest Arduino board goes all the way back to the boards that were such an important part of the history of this movement of making embedded systems accessible to everyone.