[ENHANCEMENT/BUGFIX] MathUtil additions + lerp fix

[cyn0x8]

changes:

• corrected errors in documentation for the non-deprecated functions
• moved deprecated functions to the bottom
• added helper functions fract and snap
• deprecated smoothLerp and split it into smoothLerpDecay and smoothLerpPrecision (the halfLife and duration/precision versions respectively)
• converted all uses of smoothLerp and coolLerp to (functionally identical) smoothLerpPrecision along with snap for stuff like the score numbers
• added @:keep to the class so that while source may not use all the functions, mods will still be able to

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explanation:

i like fract

also!!! the behavior of smoothLerp is incorrect... more precisely the snapping

it assumes the "origin" value is 0, which leads to this behavior:

2024-10-06.20-02-02.mp4

which can be fixed if (precision * target) is changed to precision * Math.abs(target - base)!!

2024-10-06.20-35-53.mp4

...HOWEVER
this only works for the first iteration as the base changes and thus the threshold changes
you cant snap the value after duration because its literally impossible to obtain that information without some extra variable keeping track of the "origin" value

sooo i split off the snapping behavior into its own function and made the threshold constant, separate for each use case like 1 for the song score or 0.01 for the song % completed

[cyn0x8]

everything is pretty much identical, except for the score lerp on freeplay which now goes to the last digit

2024-10-07.17-54-04.mp4