[refactor] typification of SearXNG / EngineResults

In [1] and [2] we discussed the need of a Result.results property and how we can
avoid unclear code.  This patch implements a class for the reslut-lists of
engines::

    searx.result_types.EngineResults

A simple example for the usage in engine development::

    from searx.result_types import EngineResults
    ...
    def response(resp) -> EngineResults:
        res = EngineResults()
        ...
        res.add( res.types.Answer(answer="lorem ipsum ..", url="https://example.org") )
        ...
        return res

[1] https://github.com/searxng/searxng/pull/4183#pullrequestreview-257400034
[2] https://github.com/searxng/searxng/pull/4183#issuecomment-2614301580
Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

1 files changed, 8 insertions, 0 deletions

diff --git a/docs/dev/engines/index.rst b/docs/dev/engines/index.rst
index d0a31ab67..8491681cb 100644
--- a/docs/dev/engines/index.rst
+++ b/docs/dev/engines/index.rst
@@ -19,6 +19,14 @@ Engine Implementations
    engine_overview
 
 
+ResultList and engines
+======================
+
+.. autoclass:: searx.result_types.ResultList
+
+.. autoclass:: searx.result_types.EngineResults
+
+
 Engine Types
 ============