`Enum` key for `Map` ignores `SerializationFeature.WRITE_ENUMS_USING_INDEX`

[unlimitedsola]

Version: latest 2.8

Failing unit tests added here:
https://github.com/SolaKun/jackson-databind/commit/6e095f75edd1de3eb33be5950c56d562bd6d584a

Only java.util.Map test case provided, but doesn't work with EnumMap as well..

[cowtowncoder]

Just to make sure I understand: this is when keys are Enums, not when values are Enums?

[unlimitedsola]

yes