Auto merge of #13339 - lowr:patch/change-generic-param-order, r=Veykril

fix: treat enum variants as generic item on their own

Fixup for #13335

It turns out I tried to merge two procedures into one utility function without noticing the incompatibility.

This time I *did* run analysis-stats on the four crates and confirmed it doesn't crash and this patch doesn't cause regression.