remove bizarre overflow:hidden from lists in sidebar on Vector

remove bizarre overflow:hidden from lists in sidebar on Vector

I have no idea what this rule was there for. It serves no purpose (the
bullets are already hidden by list-style-type:none several lines above
it), and it only makes it harder to add a bullet point there, e.g. to mark
featured/good articles in interwiki links. I spent 15 minutes figuring out
why the hell they are staying hidden after I set list-style-type to disc.

I believe that this one line was the sole cause of awful hacks used for
the purpose of marking FA/GA interwikis, such as the one on en.wiki[1]
or pl.wiki[2].

[1] https://en.wikipedia.org/wiki/MediaWiki:Vector.css - grep for
    {{tl|Link GA}}, {{tl|Link FA}}

[2] https://pl.wikipedia.org/wiki/MediaWiki:Gadget-featured-articles-links.css
    - grep for .skin-vector

Patchset 2: add word-wrap:break-word per Trevor's suggestion.

Change-Id: Ic993b0fbcc5e468effab3552b032ff4946c18b46