*_old username problems

[omkelderman]

after quite a few times ive seen issues with *_old usernames, tldr querying the api for username foo_old gives back data from user foo.

peppy reasons: ppy/osu-api#280 (comment)

proposed solution: filter out *_old usernames and tell them to contact us to fix username mappings as almost certainly the bot wont be able to do it on their own. Alternatively we could instruct them to use !fixid, as querying the api with userid still works as expected

@Tillerino what ya think?

[tybug]

Interestingly, replacing the _old portion of the username with just _ always (in my experience) resolves to the correct user. So searching for foo_ will return foo_old, whereas searching for foo_old will return foo. I've used this hack in u/OsuReportBot, though it's obviously not a documented feature, so not sure if you want to rely on it.

This is also a nonissue in api v2, fwiw (querying for foo_old always returns foo_old).