Added these in a previous iteration, where I had the mania variant inherit this class.
No longer necessary as `IHasColumn` was used to make this check more generic.
Will potentially have `CheckUnsnappedKiai` or similar later, so this is worth specifying.
Also consistent with `CheckConcurrentObjects`, which will likely have a `CheckConcurrentLines` later.
Here we use `IHasColumn` to support rulesets with columns, and so I moved that interface out into `osu.Game` from `osu.Game.Rulesets.Mania`.
We also use the same threshold as the unsnap check to ensure that no problems slip through. Specifically where an object is simultaneously not concurrent and not unsnapped but still on the same tick.
