Alice Munro has long been heralded for her penetrating, lyrical prose, and in “The Bear Came Over the Mountain” – the basis for Sarah Polley’s film Away From Her — her prodigious talents are once again on display. As she follows Grant, a retired professor whose wife Fiona begins gradually to lose her memory and drift away from him, we slowly see how a lifetime of intimate details can create a marriage, and how mysterious the bonds of love really are.