Several classes have a lot of non-trivial members within them, or don't
but likely should have the destructor defaulted in the cpp file for
future-proofing/being more friendly to forward declarations.
Leaving the destructor unspecified allows the compiler to inline the
destruction code all over the place, which is generally undesirable from
a code bloat perspective.
This was used in two different translation units
(deconstructed_rom_directory and patch_manager). This means we'd be
pointlessly duplicating the whole array twice due to it being defined
within the header.
