fix: toCreasedNormals(): call toNonIndexed() only on non-indexed geometries (#564)

* fix: toCreasedNormals(): call toNonIndexed() only on non-indexed geometries

* Docs: Clarify units for toCreasedAngle function

Author: Methuselah96

types/three/examples/jsm/utils/BufferGeometryUtils.d.ts

@@ -28,10 +28,11 @@ export function deinterleaveAttribute(geometry: BufferGeometry): void;
 export function deinterleaveGeometry(geometry: BufferGeometry): void;
 
 /**
- * Creates a new, non-indexed geometry with smooth normals everywhere except faces that meet at an angle greater than the crease angle.
+ * Modifies the supplied geometry if it is non-indexed, otherwise creates a new, non-indexed geometry. Returns the
+ * geometry with smooth normals everywhere except faces that meet at an angle greater than the crease angle.
  *
  * @param geometry The input geometry.
- * @param creaseAngle The crease angle.
+ * @param creaseAngle The crease angle in radians.
  */
 export function toCreasedNormals(geometry: BufferGeometry, creaseAngle?: number): BufferGeometry;