docs: clarify editableList resize* callbacks are related to physical size, not item count

Current Behavior

It appears that the resize() and resizeItem() callbacks on editableList do not get called as they should when an item is added or removed from the list, unless I am misunderstanding the docs.
resize() does get called when the node dialog is initially opened, but not thereafter and resizeItem seems never to be called at all.
I have not attempted to use them before so don't know whether they have ever worked.

See also forum post https://discourse.nodered.org/t/problem-with-editablelist-resize-callback/88263 where @marcus-j-davies confirms the behaviour (of resize at least).

Expected Behavior

No response

Steps To Reproduce

No response

Example flow

paste your flow here

Environment

• Node-RED version: 3.1.9 and 4.0.0-beta.3
• Node.js version: 20.5.1
• npm version:
• Platform/OS:
• Browser: Edge on Ubuntu

從 issue 中連結的 editableList resize 選項文件開始，並查看相關的論壇討論。明確說明 resize() 和 resizeItem() 回呼涉及的是實體大小，而不是項目數量；當其與 issue 和論壇貼文中所描述的已確認行為一致時，即可認為文件中描述的行為已經完整。