Sion (Type Moon) umbrella tag

BUR #36602 is pending approval.

create implication sion_eltnam_atlasia -> sion_eltnam_(type-moon)
create implication sion_eltnam_sokaris -> sion_eltnam_(type-moon)
create implication sion_tatari -> sion_eltnam_(type-moon)
create implication dust_of_osiris -> sion_eltnam_(type-moon)

Potential umbrella tag for the versions of TYPE-MOON's Sion Eltnam Atlasia

I'd also add Eltnum (under night in-birth) here, rather than implying Sion Eltnam Atlasia. I'd add it as a BUR but danbooru is mad about the fact that Sion Eltnam doesn't have a wiki page (yet).

Also Sion Eltnam probably doesn't need a qualifier as a base tag. Sion by itself would be ambiguous, but I don't think Sion Eltnam is.