BREAKING. Type Tag: leaving page empty now refers to current page

Instead of assuming a page named after the field, an empty "page"
configuration now always refers to the "current" page. Eg. the page on
which the tag is rendered.

A tag without a configured aggregation page will always link to the same
page. When shown in the page data, such a tag can not be easily looked
up anymore. OTOH it can be much easier be used in several aggregations.

Author: splitbrain

types/Tag.php

@@ -26,12 +26,14 @@ class Tag extends AbstractMultiBaseType
      */
     public function renderValue($value, \Doku_Renderer $R, $mode)
     {
+        global $INFO;
+
         $context = $this->getContext();
         $filter = SearchConfigParameters::$PARAM_FILTER .
             '[' . $context->getTable() . '.' . $context->getLabel() . '*~]=' . $value;
 
         $page = trim($this->config['page']);
-        if (!$page) $page = cleanID($context->getLabel());
+        if (!$page) $page = $INFO['id'];
 
         $R->internallink($page . '?' . $filter, $value);
         return true;