Previously, an option of type
attrsOf string
wouldn't throw a deprecation warning, even though the string type is
deprecated. This was because the deprecation warning trigger only looked
at the type of the option itself, not any of its subtypes.
This commit fixes this, causing each of the types deprecationMessages to
trigger for the option. This relies on the subtypes mkOptionType
attribute introduced in 26607a5a2e06653fec453c83d063cdfc4b59185f
4b54aedee5