Allow airborne fighters to pass through platforms while holding down

src/fighter/state/ground.rs

@@ -9,6 +9,7 @@ use crate::fighter::{
     FighterAttributes, FighterPreviousTranslation, FighterTranslation, FighterVelocity,
 };
 use crate::game_settings::GameSettings;
+use crate::input::FighterInput;
 use crate::math::int::{FGWide, FGi32};
 use crate::math::vec::FGVec2;
 use crate::stage::line::{StageLineID, StagePoly, StagePolyLineSegment, StagePolyLineSegmentType};