Indexing of defimpl does not map over array for :for

[KronicDeth]

defimpl, in addition to having no for: keyword argument and having an alias for the keyword value, can also take a list as the value for for: as in exjsx package:

Actual:
The :for list is used as the literal name of the defimpl defined module

Expected:
When the :for has a list value, an index entry will be made for each of the expanded names for each element in the list.