想要分离某几个Storyboard，先选中要分离的几个Storyboard，点击 Xcode 的菜单栏，选择"Editor->Refactor to Storyboard"。
/Users/istig/Desktop/03-Storyboard-References/StoryboardReferences/Base.lproj/Main.storyboard: Scene is unreachable due to lack of entry points and does not have an identifier for runtime access via -instantiateViewControllerWithIdentifier:.
会出现这个警告⚠️，把对应的segue删除便可
