Remove generator untagged enum configuration

[blt]

Consider

lading/src/config.rs

Lines 28 to 32 in 5aae408

	/// We have many uses that exist prior to the introduction of multiple
	/// blackholes, meaning many configs that _assume_ there is only one bloackhole
	/// and that they do not exist in an array. In order to avoid breaking those
	/// configs we support this goofy structure. A deprecation cycle here is in
	/// order someday.

. It is reasonable to remove the untagged enum here and require a list of generators only.