'Schitt's Creek' glances back as it moves ahead in emotional finale

Schitt's Creek ends with a declaration of love. 

In the series finale, during a ceremony presided over by Moira, with Alexis, Johnny, and the rest of the town watching on, Patrick and David finally exchanged vows: a cappella Mariah Carey from Patrick and weepy sincerity (followed by a winking inside joke) from David. 

The...