[mod] duckduckgo: restore Sec-Fetch-* headers to prevent rate limits

searx/engines/duckduckgo.py

@@ -379,6 +379,12 @@ def request(query: str, params: "OnlineParams") -> None:
     # The vqd value is generated from the query and the UA header. To be able to
     # reuse the vqd value, the UA header must be static.
     headers["User-Agent"] = _HTTP_User_Agent
+
+    headers["Sec-Fetch-Dest"] = "document"
+    headers["Sec-Fetch-Mode"] = "navigate"
+    headers["Sec-Fetch-Site"] = "same-origin"
+    headers["Sec-Fetch-User"] = "?1"
+
     headers["Referer"] = "https://html.duckduckgo.com/"
 
     ui_lang = params["searxng_locale"]