Revert "Fix comments (arkworks-rs#652)"

This reverts commit dd9ec23.

ec/src/models/short_weierstrass/mod.rs

@@ -65,7 +65,7 @@ pub trait SWCurveConfig: super::CurveConfig {
     /// Check if the provided curve point is in the prime-order subgroup.
     ///
     /// The default implementation multiplies `item` by the order `r` of the
-    /// prime-order subgroup, and checks if the result is zero.
+    /// prime-order subgroup, and checks if the result is one.
     /// Implementors can choose to override this default impl
     /// if the given curve has faster methods
     /// for performing this check (for example, via leveraging curve

ec/src/models/short_weierstrass/serialization_flags.rs

@@ -5,11 +5,11 @@ use ark_serialize::Flags;
 /// The default flags (empty) should not change the binary representation.
 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
 pub enum SWFlags {
-    /// Represents a point with positive y-coordinate by setting all bits to 0.
+    /// Represents a point with positive y-coordinate by setting the MSB to 1.
     YIsPositive = 0,
     /// Represents the point at infinity by setting the setting the last-but-one bit to 1.
     PointAtInfinity = 1 << 6,
-    /// Represents a point with negative y-coordinate by setting the MSB to 1.
+    /// Represents a point with negative y-coordinate by setting all bits to 0.
     YIsNegative = 1 << 7,
 }