[PATCH] Correct square bracket handling in URL netloc - The human representation of usernames and passwords should percent- encode square brackets. - Clean up the test suite to remove tests that use invalid hostnames (square brackets in a host name must only be used for IPv6 addresses). - Rename the remaining test using IPvFuture address syntax to make this explicit. - Drop a test for IPv6 addresses with a zone id; zone id support is controversial and expilictly excluded from the WHATWG URL standard. Zone ids *without percent characters in their name* continue to work as long as urllib.parse.urlsplit() accepts them but this is not something that yarl.URL() needs to support explicitly.
