Github-toggle-expanders: handle PR comments

I have chosen to handle the click only for the current review,
not all reviews done in the PR wich could be too much
(and less interesting from my use case -> check everything is OK for one review)
So the selector is `.discussion-item-body` and not `.js-discussion`

I had to refactor to match the closest parent.
As a consequence, there is no longer the need to support `#commits_bucket` to fix Mottie#8

github-toggle-expanders.user.js

@@ -15,15 +15,16 @@
 	"use strict";
 
 	function toggle(el) {
-		const state = closest(".commits-list-item, .js-details-container", el)
-			.classList.contains("open"),
-			// target buttons inside commits_bucket - fixes #8
-			selectors = `
-				.commits-listing .commits-list-item,
-				#commits_bucket .js-details-container,
-				.release-timeline-tags .js-details-container`;
-		Array.from(document.querySelectorAll(selectors)).forEach(el => {
-			el.classList.toggle("open", state);
+		const stateNode = closest(".js-details-container", el),
+			state = stateNode.classList.contains("open"),
+			parentNode = closest(
+				".commits-listing, .discussion-item-body, .release-timeline-tags",
+				stateNode
+			),
+			containerNodes = parentNode.querySelectorAll(".js-details-container");
+
+		Array.from(containerNodes).forEach(node => {
+			node.classList.toggle("open", state);
 		});
 	}
 
@@ -41,7 +42,7 @@
 		const target = event.target;
 		if (
 			target && event.getModifierState("Shift") &&
-			target.matches(".ellipsis-expander")
+			target.matches(".js-details-target")
 		) {
 			// give GitHub time to add the class
 			setTimeout(() => {