Fix capture logic for inner closures

[sophiajt]

Description

This fixes the variable capture logic for closures in two cases:

• Closures inside of closures did not properly register the closures (or lack thereof) in the outer closure
• Closures which called their inner closures before definition did not properly calculate the closures of the outer closure

Example of the first case:

do { let b = 3; def c [] { $b }; c }

Example of the second case (notice c is called before it is defined):

do { let b = 3; c; def c [] { $b }; c }

User-Facing Changes

This should strictly allow closures to work more correctly.

Tests + Formatting

After Submitting

[amtoine]

looks related to the end of the description of #9746

[amtoine]

i'm not sure i understand the parser well enough, by far, but the changes look good and i like the two new tests 😊

[fdncred]

Examples seem to work for me. I also tested this case, which is similar to the second case.

❯ do { let b = 3; print (c); def c [] { $b }; print (c) }
3
3

[kubouch]

I think there might still be some capturing bug left because this issue is still present: #5994