Remove duplicated comment on equatable

Author: markuswntr

Sources/QuaternionModule/Quaternion.swift

@@ -396,9 +396,6 @@ extension Quaternion where RealType: BinaryFloatingPoint {
 extension Quaternion: Hashable {
   /// Returns a Boolean value indicating whether two values are equal.
   ///
-  /// Equality is the inverse of inequality. For any values *a* and *b*,
-  /// `a == b` implies that `a != b` is `false`.
-  ///
   /// - Important:
   ///   Quaternions are frequently used to represent 3D transformations. It's
   ///   important to be aware that, when used this way, any quaternion and its