mathlib

65bf1349 - split(algebra/hom/ring): Split off `algebra.ring.basic` (#14144)

split(algebra/hom/ring): Split off `algebra.ring.basic` (#14144) Move `non_unital_ring_hom` and `ring_hom` to a new file `algebra.hom.ring`. Crediting * Amelia for #1305 * Jireh for #13430