remove dead instances from list of known instances about lemmybb

[Tealk]

this currently makes no sense because the instances are only dead because the software has a bug:
#99

[bsammon]

It makes a little bit of sense.
The documentation currently says (or implies, if you prefer) "Here's some websites you can check out". That's not currently the case.
If removing them from the list is inappropriate, maybe annotate the list with a notation "currently down due to <stuff>"

[Tealk]

Currently there are no working instances, so that might be some information to add.

[DraconicNEO]

Currently there are no working instances, so that might be some information to add.

Yeah even the Lemmy-UI domain for the second one isn't working so it seems they've folded up.

[Tealk]

it seems they've folded up

Oh no, we just changed the domain to rollenspiel.forum

[DraconicNEO]

it seems they've folded up

Oh no, we just changed the domain to rollenspiel.forum

Oh I see, I thought they closed because the domain errored.

Though it does seems like fedibb.ml has closed for good since the error on mlmym is the same as for one where the domain doesn't exist.