Minor docs edit for typedef rule (#2301)
Minor docs edit for typedef rule (#2301)


andy-hanson/tslint,mprobst/tslint,IllusionMH/tslint,andy-ms/tslint,RyanCavanaugh/tslint,berickson1/tslint,IllusionMH/tslint,JoshuaKGoldberg/tslint,palantir/tslint,andy-hanson/tslint,berickson1/tslint,berickson1/tslint,RyanCavanaugh/tslint,mprobst/tslint,andy-ms/tslint,andy-hanson/tslint,JoshuaKGoldberg/tslint,andy-ms/tslint,mprobst/tslint,JoshuaKGoldberg/tslint,IllusionMH/tslint,RyanCavanaugh/tslint,palantir/tslint,palantir/tslint