Replace x() by isset(), !empty() or defaults()

- Remove extraneous parentheses around empty() calls
- Remove duplicate calls to intval(), count() or strlen() after empty()
- Replace ternary operators outputting binary value with empty() return value
- Rewrite defaults() without x()

src/Module/Contact.php

@@ -44,7 +44,7 @@ class Contact extends BaseModule
 			$nets = '';
 		}
 
-		if (!x($a->page, 'aside')) {
+		if (empty($a->page['aside'])) {
 			$a->page['aside'] = '';
 		}