Optimise code, indicate changes in copyright headers

src/com/android/launcher3/folder/FolderAnimationManager.java

@@ -12,6 +12,8 @@
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
+ *
+ * Modifications copyright 2021, Lawnchair
  */
 
 package com.android.launcher3.folder;