Ash change that removes a graph edge from the action's record to a destination record named by an argument, after the vertex write, inside the action's transaction.
change {AshAge.Changes.DestroyEdge, edge: :author, to: :author_id}edge: names an edge entry in the resource's age do ... end block. to:
names an action argument holding the destination primary key (or a list of
keys -> N deletes). An edge that matched nothing (already gone or out of the
source's graph/tenant scope) returns Ash.Error.Changes.StaleRecord so Ash
rolls the vertex back; DB errors are redacted.
A nil or empty to: argument removes NO edge and the action still succeeds
(the removal is optional). Make to: required at the call site to force one.