Amy Schumer gives a beaut of a performance in the uneven but sweetly amusing ‘I Feel Pretty’

“I Feel Pretty” is — how to put this? — better than it looks. A mildly raunchy yukfest by way of an aspirational fairy tale, the movie stars Amy Schumer as Renee, an ordinary New Yorker who dreams of being a knockout — or, barring that, of being able to squeeze into shoes smaller than a double-wide…