[doc] Fix documentation about redis sessions
Documentation about redis sessions recommends the use of a project unmaintained since 2015 (https://pypi.org/project/pyramid_redis_sessions/ ) we should probably test and document the use of https://pypi.org/project/pyramid-session-redis/ which is "sort-of-a-drop-in-replacement" which is maintained.
-
test -
document -
find projects using pyramid_redis_sessions and help them migrate to the new one.