Integrate with pyre incremental and adapt the TypeWriter search strategy

[stroxler]

It would be interesting to see how well the TypeWriter algorithm (https://software-lab.org/publications/TypeWriter_arXiv_1912.03768.pdf) for searching type annotation suggestions works against type4py. We might get dramatically better results for two reasons:

• type4py's ML model seems to perform quite a bit better
• today's pyre incremental is orders of magnitude faster than pyre was when the TypeWriter paper was written, so we may be able to try many more combinations and get correspondingly better results

At one point we'd considered hacking this very quickly as an internal project in my company, but we ran out of time. I think it would be better done open-source anyway because then

• it would be easier to try out against external projects
• we could publish our results with code if they are interesting enough to be worth a paper
• the entire OSS community could benefit

I'm unsure if I can find time to prioritize this in the next 6 months at work but it's a little more likely if I treat it as a side project, which would also open the door to an informal weekend hackathon as a way to kick it off :)

I could do this in a separate repository or inside of type4py. What do you think @mir-am ? And does this sound interesting to you?