GLTFLoader: rename _q to _quaternion (mrdoob#30917)

Author: satelllte

examples/jsm/loaders/GLTFLoader.js

@@ -2217,15 +2217,15 @@ class GLTFCubicSplineInterpolant extends Interpolant {
 
 }
 
-const _q = new Quaternion();
+const _quaternion = new Quaternion();
 
 class GLTFCubicSplineQuaternionInterpolant extends GLTFCubicSplineInterpolant {
 
 	interpolate_( i1, t0, t, t1 ) {
 
 		const result = super.interpolate_( i1, t0, t, t1 );
 
-		_q.fromArray( result ).normalize().toArray( result );
+		_quaternion.fromArray( result ).normalize().toArray( result );
 
 		return result;