fix(docs/dotprompt/schema): use correct schemas to type inference

[DenisVCode]

Current example is wrong and does't correctly infer schema for the output. It sends only one schema, where 2 are expected, one for input, one for output.

I have followed the current docs, but replaced the single schema with 2 schemas, one for output and one for input, that would produce correctly working snippet.

Related Discord chat: https://discord.com/channels/1255578482214305893/1255934063173435402/1291469593235296439

Checklist (if applicable):

• [ ] Tested (manually, unit tested, etc.)
• [x] Docs updated