expand when anchor for folded group called & scroll after init

[HWienhold]

tried to do the second point of #76

Had somewhat trouble when calling anchor on not rendered page (also w/ master). Its a bit hard to test on diff.rs bc for some reason all calls url#... are seem to be rerouted to url/#... or sth like that idk[^1].

Beside this i am a bit confused: the snipped i used to scroll to the anchored element fails to find the object in question when called after initial rendering, so i used the workaround of changing the state in this case. Maybe you could give me some insight here?

[^1]: or maybe doing sth wrong idk - if not then this might be a bugreport

[xfbs]

I'll probably get around to reviewing this on the weekend, sorry for the delay!