add doc and correct test

modules/fontane/index-api.xqm

@@ -289,6 +289,7 @@ return
 (:~
  : Returns available image from TextGrid Repository
  : @param $id the xml:id of an entity in the database
+ : @param $type the index to look up, on of: plc, wrk, psn, eve, org
  : @return an array of URIs
  :)
 declare
@@ -297,13 +298,17 @@ declare
   %output:method("json")
 
   %test:arg("id", "Arnoldi-Denkmal")
+  %test:arg("type", "plc")
   %test:assertTrue
 function index:rendered-entity($type as xs:string, $id as xs:string)
 as item()* {
-    let $request := <hc:request method="get" href="https://textgridlab.org/1.0/tgsearch-public/search/?q=(title:%22{$type}:{$id}%22)" />
+    let $request :=
+      <hc:request
+        method="get"
+         href="https://textgridlab.org/1.0/tgsearch-public/search/?q=(title:%22{$type}:{$id}%22)" />
     let $tgsearch := hc:send-request($request)[2]
     return
         [
-        $tgsearch//tgmd:textgridUri/string()
+          $tgsearch//tgmd:textgridUri/string()
         ]
 };