Improve freeflow channel example

Have a look at tracer example for orientation 1ptracer

• Check if feature list is exhaustive

changed milestone to %3.2

added Examples label

mentioned in issue #829 (closed)

mentioned in issue #811 (closed)

mentioned in issue #831 (closed)

mentioned in issue #520 (closed)

changed the description

added Dumux Day label

changed milestone to %3.3

@nedc I think these doc/example issues should be still done in 3.2 to get a unified example layout. It's not affected the code base so it shouldn't be a problem for testing...

changed milestone to %3.2

I can have a look at this. Or has somebody else already started?

assigned to @kweis

mentioned in merge request !1976 (merged)

What needs to be done about the feature list?

Check if all features that are shown in the example are listed in the example main page and the example intro, if not add new features

marked the checklist item Check if feature list is exhaustive as completed

closed via merge request !1976 (merged)

mentioned in commit 2c74b446

mentioned in commit bf8fdae6

mentioned in merge request !1995 (merged)