Fix Bug 28979 — “remove some CSS for abbr and acronym tags”

Fix Bug 28979 — “remove some CSS for abbr and acronym tags”

    The <abbr> and <acronym> tags were whitelisted with bug 671, but
    there are some CSS rules for them since long, long times. They can
    be found in the first versions of chick, monobook and are carried
    on to vector skin.

    Often these tags are used in links, e.g. [[Normalnull|<abbr
    title="meter above see level">NN</abbr>]]. But in here the
    color:black; makes the text unrecognizable as a hyperlink
    (together with the senseful cursor:help; rule).

    When these rules where meant to override some crazy
    browserdependent default settings, they should be be changed to
    "inherit".

from Bergi