Clear up ambiguity in the intial rotation example

When a user is seeing transform.basis for the first time, it's
very important to label all the inputs. People reading this are
being presented with several values at once and must understand
all of them to understand what is happening in the example. The
reader is likely unfamiliar with what `transform.basis` actually
does. They are also given a Vector3 without explanation that it
is the axis, they are given PI without explanation that that is
the amount of rotation, they are multiplying by the value of the
transform.basis again hinging on them understanding what that is.
Finally, they are creating a Basis object and it's not made clear
that the two values this receives are actually an axis and an
amount.

Rotating by PI makes the rotation direction very unclear.

I'm introducing the changes above to hopefully rectify a lot of
these issues and make things easier for the next person.

Thanks to Aaron Franke for:

- Adds types to the C# code
- Fixes a misnamed variable
- Clearing up some of the code comments
- Changes vectors so they are consistent with the GDScript examples
- fixing float values so they are correct and consistent

Co-authored-by: Aaron Franke <[email protected]>

tutorials/3d/using_transforms.rst

@@ -149,34 +149,38 @@ It is possible to rotate a transform, either by multiplying its basis by another
 .. tabs::
  .. code-tab:: gdscript GDScript
 
-    # Rotate the transform about the X axis
-    transform.basis = Basis(Vector3(1, 0, 0), PI) * transform.basis
+    var axis = Vector3(1, 0, 0) # Or Vector3.RIGHT
+    var rotation_amount = 0.1
+    # Rotate the transform around the X axis by 0.1 radians.
+    transform.basis = Basis(axis, rotation_amount) * transform.basis
     # shortened
-    transform.basis = transform.basis.rotated(Vector3(1, 0, 0), PI)
+    transform.basis = transform.basis.rotated(axis, rotation_amount)
 
  .. code-tab:: csharp
 
-    // rotate the transform about the X axis
-    transform.basis = new Basis(Vector3.Right, Mathf.Pi) * transform.basis;
+    Vector3 axis = new Vector3(1, 0, 0); // Or Vector3.Right
+    float rotationAmount = 0.1f;
+    // Rotate the transform around the X axis by 0.1 radians.
+    transform.basis = new Basis(axis, rotationAmount) * transform.basis;
     // shortened
-    transform.basis = transform.basis.Rotated(Vector3.Right, Mathf.Pi);
+    transform.basis = transform.basis.Rotated(axis, rotationAmount);
 
 A method in Spatial simplifies this:
 
 .. tabs::
  .. code-tab:: gdscript GDScript
 
-    # Rotate the transform in X axis
-    rotate(Vector3(1, 0, 0), PI)
+    # Rotate the transform around the X axis by 0.1 radians.
+    rotate(Vector3(1, 0, 0), 0.1)
     # shortened
-    rotate_x(PI)
+    rotate_x(0.1)
 
  .. code-tab:: csharp
 
-    // Rotate the transform about the X axis
-    Rotate(Vector3.Right, Mathf.Pi);
+    // Rotate the transform around the X axis by 0.1 radians.
+    Rotate(new Vector3(1, 0, 0), 0.1f);
     // shortened
-    RotateX(Mathf.Pi);
+    RotateX(0.1f);
 
 This rotates the node relative to the parent node.
 
@@ -185,13 +189,13 @@ To rotate relative to object space (the node's own transform), use the following
 .. tabs::
  .. code-tab:: gdscript GDScript
 
-    # Rotate locally
-    rotate_object_local(Vector3(1, 0, 0), PI)
+    # Rotate around the object's local X axis by 0.1 radians.
+    rotate_object_local(Vector3(1, 0, 0), 0.1)
 
  .. code-tab:: csharp
 
-    // Rotate locally
-    RotateObjectLocal(Vector3.Right, Mathf.Pi);
+    // Rotate around the object's local X axis by 0.1 radians.
+    RotateObjectLocal(new Vector3(1, 0, 0), 0.1f);
 
 Precision errors
 ================