Fixing indentation and template parameters

Changing indentation to tab from 5 spaces for b. Also, change the formatting for template parameter to remove parentheses.

std/experimental/ndslice/selection.d

@@ -103,7 +103,7 @@ template pack(K...)
 
     auto r = (3 * 4 * 5 * 6).iota;
     auto a = r.sliced(3, 4, 5, 6);
-    auto b = a.pack!(2);
+    auto b = a.pack!2;
 
 	assert(b.shape == [3, 4]);
 	assert(b[0, 0].shape == [5, 6]);