A profile of comedy legend Carol Burnett, who entertained viewers each week from 1967 to 1979 with her eponymous sketch-comedy show; and branched into serious drama with such fare as the teleplay “Friendly Fire.” Included: clips from her classic series and “The Garry Moore Show,” which helped launch her career. Also: comments from Tim Conway and Harvey Korman, who costarred in her TV series; Julia Andrews; and Tracey Ullman.