docs: update solidstart examples

[JesusP2]

Noticed solidstart examples for sessions were outdated.

I decided to use event.locals instead of event.nativeEvent.context because it's what is mentioned in solidstart docs.

[pilcrowOnPaper]

Looks like we just use getRequestHeader() etc?

https://vinxi.vercel.app/api/server/request.html

[JesusP2]

yeah you're right. It seems like getHeader is just an alias for getRequestHeader

[pilcrowOnPaper]

From the docs, look like you can just pass event instead of nativeEvent

[JesusP2]

I just tested it and at least for solidstart it must be nativeEvent otherwise you get a ts and runtime error.

Actually solidstart has asyncContext enabled by default so you don't even need to pass the event.