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

从 issue 中链接的 editableList resize 选项文档开始，并查看相关的论坛讨论。明确 resize() 和 resizeItem() 回调涉及的是物理尺寸，而不是项目数量；当其与 issue 和论坛帖子中所描述的已确认行为一致时，即可认为文档中描述的行为已经完整。