[enh] Add woxikon.de synonyme (xpath)

Upstream example query:
https://synonyme.woxikon.de/synonyme/test.php

searx/settings.yml

@@ -1492,6 +1492,23 @@ engines:
     timeout: 5.0
     disabled: True
 
+  - name : woxikon.de synonyme
+    engine : xpath
+    shortcut : woxi
+    categories : general
+    timeout : 5.0
+    disabled : True
+    search_url : https://synonyme.woxikon.de/synonyme/{query}.php
+    url_xpath : //div[@class="upper-synonyms"]/a/@href
+    content_xpath : //div[@class="synonyms-list-group"]
+    title_xpath : //div[@class="upper-synonyms"]/a
+    about:
+      website: https://www.woxikon.de/
+      wikidata_id: # No Wikidata ID
+      use_official_api: false
+      require_api_key: false
+      results: HTML
+
   - name: słownik języka polskiego
     engine: sjp
     shortcut: sjp