[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/engines/sqlite.py

@@ -44,7 +44,7 @@ Implementations
 ===============
 
 """
-import typing
+import typing as t
 import sqlite3
 import contextlib
 
@@ -59,7 +59,7 @@ database = ""
 query_str = ""
 """SQL query that returns the result items."""
 
-result_type: typing.Literal["MainResult", "KeyValue"] = "KeyValue"
+result_type: t.Literal["MainResult", "KeyValue"] = "KeyValue"
 """The result type can be :py:obj:`MainResult` or :py:obj:`KeyValue`."""
 
 limit = 10