Fix comment in namespace registry protobuf
This changes the comment in the proto to match the existing code in the
CLI.
@@ -17,7 +17,7 @@ syntax = "proto3";
// A namespace registry is stored using the namespace, prefixed with zero
// padding:
//
-// 00ec00 + 00 padding + substr(namespace, 0, 6)
+// 00ec00 + hash(namespace)
//
// The stored contents are a serialized NamespaceRegistryList message to handle
// hash collisions.
