The plans were set. On January 17, 2022—Betty White’s 100th birthday—movie theaters around the country would premiere a new documentary called Betty White: 100 Years Young—A Birthday Celebration. With special guests that include Tina Fey, Robert Redford, Lin Manuel-Miranda, Carol Burnett, Jimmy Kimmel, Valerie Bertinelli and, of course, close friend Ryan Reynolds, everyone was invited to cheer on a woman who wasn’t just an adored entertainer, but also a beacon of joy and hope for admirers of…