promise-function-async: add options to specify function types to check. (#3807)
promise-function-async: add options to specify function types to check. (#3807)

This is useful if you only want your function and method declarations
to warn, or in other words, one doesn't want each arrow function that
is passed to Promise#then() or Promise#catch() to be async.
mprobst/tslint,palantir/tslint,andy-hanson/tslint,mprobst/tslint,palantir/tslint,andy-ms/tslint,mprobst/tslint,JoshuaKGoldberg/tslint,JoshuaKGoldberg/tslint,JoshuaKGoldberg/tslint,palantir/tslint,andy-hanson/tslint,andy-ms/tslint,andy-ms/tslint,andy-hanson/tslint