Minor edits.

docs/DifferentiableTypes.md

@@ -96,11 +96,13 @@ public protocol Differentiable {
         where TangentVector.TangentVector == TangentVector,
               TangentVector.CotangentVector == CotangentVector,
               TangentVector.AllDifferentiableVariables == TangentVector
+
     /// The cotangent bundle of this differentiable manifold.
     associatedtype CotangentVector: AdditiveArithmetic & Differentiable
         where CotangentVector.TangentVector == CotangentVector,
               CotangentVector.CotangentVector == TangentVector,
               CotangentVector.AllDifferentiableVariables == CotangentVector
+
     /// The type of all differentiable variables in this type.
     associatedtype AllDifferentiableVariables: Differentiable
         where AllDifferentiableVariables.AllDifferentiableVariables == AllDifferentiableVariables,
@@ -111,10 +113,10 @@ public protocol Differentiable {
     var allDifferentiableVariables: AllDifferentiableVariables { get }
 
     /// Returns `self` moved along the value space towards the given tangent vector.
-    /// In Riemannian geometry (mathematics), this represents an exponential map.
+    /// In Riemannian geometry (mathematics), this represents exponential map.
     func moved(along direction: TangentVector) -> Self
 
-    /// Convert a cotangent vector to its corresponding tangent vector.
+    /// Converts a cotangent vector to its corresponding tangent vector.
     func tangentVector(from cotangent: CotangentVector) -> TangentVector
 }
 ```