InitializeOnStartup documentation missing

### Product

Hot Chocolate

### Is your feature request related to a problem?

InitializeOnStartup in version 13.2.0 has new parameter warmup. How should I use it? If I leave it empty is the warmup still executed?

### The solution you'd like

Update documentation for InitializeOnStartup in https://chillicream.com/docs/hotchocolate/v13/performance