Auto merge of #14341 - stshine:where-is-the-top, r=mrobinson,emilio

script: Fix the scroll to top behavior

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When finding the indicated fragment, do not use the document element to indicate
the top of the Document, and when scrolling to the frament and we do not find a
element, scrolling the top if the fragment is empty or equal to "top".

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- [ ] These changes fix #__ (github issue number if applicable).

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