Add transformation documentation

Author: markuswntr

Sources/QuaternionModule/Transformation.md

@@ -1,10 +1,18 @@
 # Transformation
 
-`Rotation.swift` encapsulates an API for working with other forms of rotation representations, such as *Angle/Axis*, *Polar* or *Rotation Vector*. The API provides conversion from these representations to `Quaternion` and vice versa. Additionally, the API provides a method to directly rotate an arbitrary vector by a quaternion and thus avoids the calculation of an intermediate representation to any other form in the process.
+`Transformation.swift` encapsulates an API for working with other representations of transformations, such as *Angle-Axis*, *Polar* and *Rotation Vector*. The API provides operations to convert from these representations to `Quaternion` and vice versa.  
+Additionally, the API provides a method to directly rotate an arbitrary vector by a quaternion and thus avoids the calculation of an intermediate representation to any other form in the process.
 
 ## Policies
- - zero and non-finite quaternions have an indeterminate angle and axis. Thus,
-   the `angle` property of `.zero` or `.infinity` is `RealType.nan`, and the
-   `axis` property of `.zero` or `.infinity` is `.nan` in all lanes.
- - Quaternions with `angle == .zero` have an indeterminate axis. Thus, the
-   `axis` property is `.nan` in all lanes.
+
+- zero and non-finite quaternions have indeterminate transformation properties and can not be converted to another representation. Thus, 
+  
+    - The `angle` property of `.zero` or `.infinity` is `RealType.nan`. 
+    - The `axis` property of `.zero` or `.infinity` is `RealType.nan` in all lanes.
+    - The `rotationVector` property of `.zero` or `.infinity` is `RealType.nan` in all lanes.
+
+- Quaternions with `angle == .zero` have an indeterminate axis. Thus,
+
+    - the `axis` property of `angle == .zero` is `RealType.nan` in all lanes.
+    - the `rotationVector` property of `angle == .zero` is `RealType.nan` in all lanes.
+