[wpimath] Fix incorrect docs for Rotation3d default constructor (#6571)

A Rotation3d is not defined by one angle.

wpimath/src/main/native/include/frc/geometry/Rotation3d.h

@@ -20,7 +20,7 @@ namespace frc {
 class WPILIB_DLLEXPORT Rotation3d {
  public:
   /**
-   * Constructs a Rotation3d with a default angle of 0 degrees.
+   * Constructs a Rotation3d representing no rotation.
    */
   Rotation3d() = default;