Improve the comment about `objectType` property in `cardano-wasm`

[palas]

The comment about the objectType:

cardano-api/cardano-wasm/lib-wrapper/cardano-api.d.ts

Line 14 in 22f8005

* The type of the object, used for identification (the "CardanoApi" string).

Should include examples of objects types. Even better if we can automatically list all of the possible object types.