Simplify core_functions/inspect/list/nested

Refs #1382

Author: glebm

spec/core_functions/inspect.hrx

@@ -373,7 +373,7 @@ a {
 
 <===> list/nested/input.scss
 a {
-  $a: inspect([() (())]);
+  $a: inspect([() ()]);
   a: $a;
   b: type-of($a);
 }