revive hipthrusts's ability to "guess" types from previous stages

[trycatchal]

I'm not sure how this can be done or where, but similar to how rxjs eliminates the need for you to explicitly type parameters in the next pipe in line, hipthrusts should do the same...
Maybe there should be a TGuessedTypes that spits out partials and have HTPipe use it ... or have lower-level TGuessedTypes<>'s so that even if you're building multiple stages in a single object it already suggests stuff... i don't know.

Also after this revive the tests for it at the top that have been commented out

[trycatchal]

We should also look at what we have for the previous OO version of HTPipe ... AFAIR that implements the "guess" version but not the non-guess version that pushes unfulfilled inputs back... I think we have all the lego-pieces, just not the grand solution.

After this we also need a followup-issue to revive the *From's too - see the "OOP" branch (diff it against the "pre-split" branch or whatever it's called)