Rename Pokemon.Position properties

[manueldidonna]

interface Pokemon {
    data class Position(
        /**
         * The index of the [Storage] in the [StorageCollection].
         * @see StorageCollection.getStorage
         */
        val storageIndex: Int,

        /**
         * The index of the [Pokemon] in the [Storage].
         * @see Storage.get
         */
        val pokemonIndex: Int,
    )
}