Time and memories flow like water in “Aftersun,” the Scottish writer-director Charlotte Wells’ singular feature debut. It is not a generalized sort of tear-jerker about parents and children. It is a film, rather, about one child, as seen from the perspective of the child’s adult self, and one parent, the girl’s fond, troubled father. Clearly, it found its way on the page, and as filmed, with two excellent leading actors. But something magical occurred when Wells collaborated with the inspired editor Blair McClendon. That’s when the filmmaker saw what she had, and what her mosaic of memory, fee…
