docs: add godoc comments to all exported functions and methods

mc/util/math.go

@@ -2,10 +2,12 @@ package util
 
 import "math"
 
+// FloorDiv returns floor division (rounds toward negative infinity).
 func FloorDiv(a, b int32) int32 {
 	return (a - ((a%b + b) % b)) / b
 }
 
+// BpeByNum returns the minimum bits per element needed to represent x distinct values.
 func BpeByNum(x float64) uint8 {
 	return uint8(math.Ceil(math.Log2(x)))
 }