Remove unused summary

[kleinfreund]

The summary variable is never referenced in its scope and has no apparent purpose.

[javan]

Thanks, it looks like this got borked in the rewrite. We were previously setting aria-expanded on the <summary> element:

details-element-polyfill/src/details-element-polyfill/polyfill.coffee.erb

Lines 63 to 71 in 9d823e0

	polyfillToggle = ->
	onTogglingTrigger (element) ->
	summary = element.querySelector("summary")
	if element.hasAttribute("open")
	element.removeAttribute("open")
	summary.setAttribute("aria-expanded", false)
	else
	element.setAttribute("open", "")
	summary.setAttribute("aria-expanded", true)

@muan, which one is correct? Should aria-expanded live on <details> or <summary>?. Based on the W3C guide, I would think it belongs on <details>, e.g.:

<details aria-expanded="true" open>…</details>
<details aria-expanded="false">…</details>

[kleinfreund]

Keep in mind that it’s currently set on both details and summary. Further down, there is another line setting the initial aria-expanded on the summary element. (im currently on mobile)

[javan]

Right, we previously only set it on <summary> (see prior code above), which is why the variable you removed in this PR exists. I accidentally changed it to <details> in 1d17534#diff-1fdf421c05c1140f6d71444ea2b27638R68.

[muan]

It should be on summary(the “button” in this case). Quoted from references in #5:

When the details element content is shown, on the summary element (ROLE_SYSTEM_PUSHBUTTON), set STATE_SYSTEM_EXPANDED.