0.5.1: typed decoders for #Blob-heap signature payloads.
Currently covers CustomAttribute (ECMA-335 II.23.3) and
MarshalSpec (II.23.4). The full ECMA-335 II.23.2
signature-blob grammar (MethodDef/Ref/FieldSig/PropertySig/
LocalVarSig/TypeSpec/MethodSpec + recursive TypeSig) is
intentionally NOT here yet — see the module docs.
Typed signature-blob decoders for #Blob heap entries
(dnfile-rs 0.5.1).