WIP: first part of mutual recursion is done.

This involves creating the function definition and detecting cycles.
The remaining part is to "fix" the call sites
of the mutually recursive functions

crates/aiken-lang/Cargo.toml

@@ -26,6 +26,7 @@ thiserror = "1.0.39"
 vec1 = "1.10.1"
 uplc = { path = '../uplc', version = "1.0.17-alpha" }
 num-bigint = "0.4.3"
+petgraph = "0.6.3"
 
 [target.'cfg(not(target_family="wasm"))'.dependencies]
 chumsky = "0.9.2"