Remove slow Array.from, use $.fn.get (#443)

* Remove Array.from from diffheader.js

* Remove Array.from from shownames.js

extension/diffheader.js

@@ -78,7 +78,7 @@ window.diffFileHeader = (() => {
 			return;
 		}
 
-		const files = Array.from($('.file.js-details-container'));
+		const files = $('.file.js-details-container').get();
 		return files.find(el => isFilePartlyVisible(el, toolbarHeight));
 	};
 

extension/show-names.js

@@ -18,7 +18,7 @@ window.showRealNames = () => {
 	};
 
 	getCachedUsers((users = {}) => {
-		const usersOnPage = Array.from($('.js-discussion .author')).map(el => el.innerText);
+		const usersOnPage = $('.js-discussion .author').get().map(el => el.innerText);
 		const uniqueUsers = new Set(usersOnPage);
 
 		// Add cached users to DOM first, since the calls for everyone else will be slow