mathlib3

b91d3449 - chore(data/equiv/*): rename `trans_symm` and `symm_trans` to `self_trans_symm` and `symm_trans_self`. (#10309)

chore(data/equiv/*): rename `trans_symm` and `symm_trans` to `self_trans_symm` and `symm_trans_self`. (#10309) This frees up `symm_trans` to state `(a.trans b).symm = a.symm.trans b.symm`. These names are consistent with `self_comp_symm` and `symm_comp_self`.