friend method
Adds the Redditor as a friend. note
is an optional string that is
associated with the friend entry. Providing note
requires Reddit Gold.
Implementation
Future<void> friend({String note = ''}) async =>
_throwOnInvalidRedditor(() async => await reddit.put(
apiPath['friend_v1'].replaceAll(_userRegExp, _name),
body: {'note': note}));