Parse it default parameter

[k0kubun]

close #2052

[kddnewton]

One small change and then great! Thanks!

[kddnewton]

I think this might be more complicated than this unfortunately.

If you get it {} I think it needs to change back into a method call. This is also the case for when it receivers arguments without parentheses.

[k0kubun]

I tried some of such cases with local Prism.parse, and they seemed working. Though I guess I'm still missing something for passing lex-ruby/discourse/top-100, so I'll look into them.

We've fixed all cases except for pattern matching => ^it. Do we want to address it in this PR, or could that be a separate PR?

[kddnewton]

I think we should add => ^it in this PR. Also we will need to document that the local variable read nodes for it will actually use 0it for the constant name, since that's pretty weird.

Fixed those two things 313be8e 24a2872. I think that's it?

[eregon]

Could you add a test ensuring that with version 3_3_0 (Prism.parse(code, version: ...)) { it } is parsed as a method call?
That seems good to add and should help ensure the right checks are in place.

addressed the feedback in 9778377 and 94ecb36.

[kddnewton]

Great job @k0kubun!