Improve HTML a and img clipping

[TCOTC]

改进链接和图片元素粘贴和剪藏

In what scenarios do you need this feature?

网页：https://github.com/pyload/pyload

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一、复制粘贴：（少了 3 个）

default.webm

二、剪藏：（少了 2 个，并多出几个链接）

[88250]

• 链接嵌套图片的情况下只能把链接放到后面了
• 少了图片的情况稍后解决