Add support for finally on try blocks on the compiler.

[NotJustAnna]

com.github.adriantodt.lin.compiler.NodeCompiler#visitTryExpr(NodeCompiler:420):

Honestly, I don't have much idea on how to implement the finally block.

[NotJustAnna]

LeanVM is now a thing (see adriantodt/leanvm).

Further investigation will be needed to see if Lin truly needs finally support on try blocks.