docs: update examples + readme

examples/configs/groupby.ini

@@ -4,12 +4,19 @@ root = /
 slug = config/{key}.html
 template = example-config.html
 split = ' '
+key_obj_fn = '{}-z-{}'.format(X.upper(), ARGS.key.fieldKey) if X else None
+replace_none_key = unknown
 
 [testA.children]
 order_by = -title, body
 
+[testA.pagination]
+enabled = true
+per_page = 1
+url_suffix = .page.
+
 [testA.fields]
-title = "Tagged: " ~ this.group
+title = "Tagged: " ~ this.key_obj
 
 [testA.key_map]
 Blog = News