Merge pull request #1540 from pixiv/deprecate-removeunnecessaryjoints

feat: put a deprecation warning to VRMUtils.removeUnnecessaryJoints

Author: 0b5vr

packages/three-vrm/src/VRMUtils/removeUnnecessaryJoints.ts

@@ -10,6 +10,8 @@ import * as THREE from 'three';
  * Also, this function might significantly improve the performance of mesh skinning.
  *
  * @param root Root object that will be traversed
+ *
+ * @deprecated `removeUnnecessaryJoints` is deprecated. Use `combineSkeletons` instead. `combineSkeletons` contributes more to the performance improvement. This function will be removed in the next major version.
  */
 export function removeUnnecessaryJoints(
   root: THREE.Object3D,
@@ -27,6 +29,10 @@ export function removeUnnecessaryJoints(
     experimentalSameBoneCounts?: boolean;
   },
 ): void {
+  console.warn(
+    'VRMUtils.removeUnnecessaryJoints: removeUnnecessaryJoints is deprecated. Use combineSkeletons instead. combineSkeletons contributes more to the performance improvement. This function will be removed in the next major version.',
+  );
+
   const experimentalSameBoneCounts = options?.experimentalSameBoneCounts ?? false;
 
   // Traverse an entire tree, and collect all skinned meshes