Infer and display expected result type from procedure

[aidansunbury]

Is your feature request related to a problem? Please describe.
It is impossible to know the expected return type of a procedure from trpc-ui before it is run. Addressing this would be a nice quality of life fix.

Describe the solution you'd like
Swagger displays expected output values. These typically have to be defined in the spec, however the whole point of tRPC is type inference. It should be possible to at least display the return type of a procedure.

[aidansunbury]

This will only be possible if the procedure is using output validators, but could still be useful when output validators are defined.