enable kzg and aplonk by default (!172)

This MR enables by default `kzg` and `aplonk`. By doing that, both modules should be visible in the doc.

Cargo.toml

@@ -43,6 +43,9 @@ kzg = ["dep:ark-poly-commit"]
 aplonk = ["dep:ark-poly-commit"]
 fs = []
 
+[package.metadata.docs.rs]
+features = ["kzg", "aplonk"]
+
 [[example]]
 name = "kzg"
 required-features = ["kzg"]