[fix] engine & network issues / documentation and type annotations

This patch fixes some quirks and issues related to the engines and the network.
Each engine has its own network and this network was broken for the following
engines[1]:

- archlinux
- bing
- dailymotion
- duckduckgo
- google
- peertube
- startpage
- wikipedia

Since the files have been touched anyway, the type annotaions of the engine
modules has also been completed so that error messages from the type checker are
no longer reported.

Related and (partial) fixed issue:

- [1] https://github.com/searxng/searxng/issues/762#issuecomment-1605323861
- [2] https://github.com/searxng/searxng/issues/2513
- [3] https://github.com/searxng/searxng/issues/2515

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

2 files changed, 16 insertions, 4 deletions

diff --git a/searx/enginelib/__init__.py b/searx/enginelib/__init__.py
index 00962e215..fd3019e6c 100644
--- a/searx/enginelib/__init__.py
+++ b/searx/enginelib/__init__.py
@@ -17,7 +17,7 @@
 
 
 from __future__ import annotations
-from typing import Union, Dict, List, Callable, TYPE_CHECKING
+from typing import List, Callable, TYPE_CHECKING
 
 if TYPE_CHECKING:
     from searx.enginelib import traits
@@ -134,3 +134,15 @@ class Engine:  # pylint: disable=too-few-public-methods
           require_api_key: true
           results: HTML
     """
+
+    using_tor_proxy: bool
+    """Using tor proxy (``true``) or not (``false``) for this engine."""
+
+    send_accept_language_header: bool
+    """When this option is activated, the language (locale) that is selected by
+    the user is used to build and send a ``Accept-Language`` header in the
+    request to the origin search engine."""
+
+    tokens: List[str]
+    """A list of secret tokens to make this engine *private*, more details see
+    :ref:`private engines`."""
diff --git a/searx/enginelib/traits.py b/searx/enginelib/traits.py
index ae27d46f1..8a7356ce2 100644
--- a/searx/enginelib/traits.py
+++ b/searx/enginelib/traits.py
@@ -13,6 +13,7 @@ used.
 from __future__ import annotations
 import json
 import dataclasses
+import types
 from typing import Dict, Iterable, Union, Callable, Optional, TYPE_CHECKING
 from typing_extensions import Literal, Self
 
@@ -82,8 +83,7 @@ class EngineTraits:
     """
 
     custom: Dict[str, Union[Dict[str, Dict], Iterable[str]]] = dataclasses.field(default_factory=dict)
-    """A place to store engine's custom traits, not related to the SearXNG core
-
+    """A place to store engine's custom traits, not related to the SearXNG core.
     """
 
     def get_language(self, searxng_locale: str, default=None):
@@ -228,7 +228,7 @@ class EngineTraitsMap(Dict[str, EngineTraits]):
 
         return obj
 
-    def set_traits(self, engine: Engine):
+    def set_traits(self, engine: Engine | types.ModuleType):
         """Set traits in a :py:obj:`Engine` namespace.
 
         :param engine: engine instance build by :py:func:`searx.engines.load_engine`