[mod] addition of various type hints / tbc

- pyright configuration [1]_
- stub files: types-lxml [2]_
- addition of various type hints
- enable use of new type system features on older Python versions [3]_
- ``.tool-versions`` - set python to lowest version we support (3.10.18) [4]_:
  Older versions typically lack some typing features found in newer Python
  versions.  Therefore, for local type checking (before commit), it is necessary
  to use the older Python interpreter.

.. [1] https://docs.basedpyright.com/v1.20.0/configuration/config-files/
.. [2] https://pypi.org/project/types-lxml/
.. [3] https://typing-extensions.readthedocs.io/en/latest/#
.. [4] https://mise.jdx.dev/configuration.html#tool-versions

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

searx/data/core.py

@@ -9,9 +9,9 @@ from searx.cache import ExpireCacheCfg, ExpireCacheSQLite
 
 log = logger.getChild("data")
 
-data_dir = pathlib.Path(__file__).parent
+data_dir: pathlib.Path = pathlib.Path(__file__).parent
 
-_DATA_CACHE: ExpireCacheSQLite = None  # type: ignore
+_DATA_CACHE: ExpireCacheSQLite | None = None
 
 
 def get_cache():