Simplify recvString output

[ivanruski]

Refactor recvString to return only type's name without it's type
parameters when the type is generic.

In this way type's string representation will be consistent with
function's string representation(gocognit print only function's name
even if it's generic one).

[uudashr]

Thanks a lot

[ivanruski]

No worries, I enjoyed the whole thing and during the process I learned how to write Go code for multiple Go versions.