Browsers such as Chrome and Firefox apply an arbitrary scale to the
current font size if `normal` is used for `line-height`. Firefox uses
1.2 while Chrome uses 1.15. Let's go with the latter for now, it's
relatively easy to change if we ever want to go back on that decision.
This also requires updating the expectations for a lot of layout tests.
The upside of this is that it's a bit easier to compare our layout
results to other browsers', especially Chrome.
On any `display: list-item` Node a CSS pseudo element (`::marker`) needs
to be created. This commit allows the ::maker pseudo element to be
nested within other pseudo elements (e. g. ::before or ::after).
This fixes this WPT test:
http://wpt.live/css/CSS2/generated-content/after-content-display-003.xht
