[ticket/12580] Remove :link pseudo from a tag

removed the :link pseudo from a tag as due to specificity it prevents
classes from altering any properties set to it.

PHPBB3-12580
Merge remote-tracking branch 'hanakin/ticket/12580' into develop-ascraeus

* hanakin/ticket/12580:
  [ticket/12580] Remove :link pseudo from a tag
Merge branch 'develop-ascraeus' into develop

* develop-ascraeus:
  [ticket/12580] Remove :link pseudo from a tag