Remove html.elements.button.autocomplete

[skyclouds2001]

Summary

as the data added in #19949 , this attribute is not supported in Firefox 121 as I test; also no info that <button> html element has ever supported this attribute searched in Firefox release or bugs

content update mdn/content#31605

autocomplete attribute spec https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#attr-fe-autocomplete
form spec https://html.spec.whatwg.org/multipage/forms.html#the-form-element
input spec https://html.spec.whatwg.org/multipage/input.html#the-input-element
select spec https://html.spec.whatwg.org/multipage/form-elements.html#the-select-element
textarea spec https://html.spec.whatwg.org/multipage/form-elements.html#the-textarea-element

this also relates with #21790

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update later when doing content update:

in mdn docs for <button> element

it suggest two links - https://stackoverflow.com/questions/5985839/bug-with-firefox-disabled-attribute-of-input-not-resetting-when-refreshing and https://bugzilla.mozilla.org/show_bug.cgi?id=654072, but they are discussing about <input type="button" />, not <button> element

so I guess this attribute is added incorrectly

Test results and supporting details

Related issues

[Elchi3]

Makes sense to me, thank you! 👍