Drop outdated engine attributes: supported_languages, language_aliases
Complete, normalize and document the type definitions for the engine-module and
engine-class.
For the ``engine.about`` section of the configuration, a type check is performed
based on structure ``searx.enginelib.EngineAbout``.
The property ``engine.about.language`` no longer exists; existing values have
been migrated to ``engine.language``.
Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>
T-Online_ is a German news portal.
It gets its web results from Google, image results from Flickr and videos results
from YouTube.
For images and videos, it additionally returns result from its
news catalog. However, for pagination we have to specify the result
type (e.g. either videos from YouTube or from T-Online), so we use
flickr/youtube there instead of tonline because the tonline results
are usually irrelevant.
Markus Heiser