Breadcrumbs: Warn against infinite loop

[NorfairKing]

Hi! Every once in a while I accidentally make an infinite loop in breadcrumbs, which then locks up my computer entirely.
Is there any chance we could give this code a recursion limit or a loop detector?

yesod/yesod-core/src/Yesod/Core/Class/Breadcrumbs.hs

Lines 28 to 31 in c59993f

	go back Nothing = return back
	go back (Just this) = do
	(title, next) <- breadcrumb this
	go ((this, title) : back) next

[snoyberg]

Seems OK, PR welcome.

[jezen]

I believe this is fixed in #1728 so I'll close this issue.