Add support for logged out 404 pages (#174)

Author: gamemaker1

index.ts

@@ -12,7 +12,7 @@ addTests('__urls_that_dont_match__', [
 	'https://github.com/sindresorhus/refined-github/issues/templates/edit',
 ]);
 
-export const is404 = (): boolean => document.title.startsWith('Page not found · GitHub'); // #98
+export const is404 = (): boolean => /^(Page|File) not found · GitHub/.test(document.title); // #98; When logged out, it starts with "File"
 
 export const is500 = (): boolean => document.title === 'Server Error · GitHub' || document.title === 'Unicorn! · GitHub' || document.title === '504 Gateway Time-out';
 

test.ts

@@ -72,6 +72,9 @@ test('is404', t => {
 	document.title = 'Page not found · GitHub';
 	t.true(pageDetect.is404());
 
+	document.title = 'File not found · GitHub';
+	t.true(pageDetect.is404());
+
 	document.title = 'examples/404: Page not found examples';
 	t.false(pageDetect.is404());