This change refactors `GetAdjustedDisplayDifficulty()` and
`GetBeatmapAttributesToDisplay()` in two ways:
- Both methods now accept `IBeatmapInfo` instead of
`IBeatmapDifficultyInfo`. This is done in order to make mania key
count display to work, wherein `IBeatmapDifficultyInfo` is not enough
to calculate the final key count.
- `GetAdjustedDisplayDifficulty()` now applies all
`IApplicableToDifficulty` mods itself. I did this after noticing that
every real consumer of this method had to do that themselves for very
little reason.
Bartłomiej Dach
7c4dd812b6