Comment 2 for bug 256697

After discussion I've decided that a JSON-encoded list is the best way to represent the list of tags, even in an argument to a named operation. However, it should be possible to make launchpadlib serialize lists and other non-strings to JSON data structures transparently.

I'm not sure how the "separated by spaces" thing ended up in the documentation for that method, but at any rate it should be changed to "a list."