CharacterData.cpp still handled the style invalidation fallout from text
mutations under dir=auto ancestors directly. Move that behavior into the
CSS language invalidation helper.
CharacterData continues to own text replacement and layout text updates.
The helper now owns the inherited :dir() restyle and :has(:dir(...))
ancestor scheduling that can follow from text content changes.
Element.cpp still handled the CSS invalidation fallout from dir and lang
attribute changes directly. Move the descendant style dirtiness and
:has(:dir/:lang) ancestor scheduling into CSS::Invalidation.
Element continues to parse and store the DOM-facing attribute state. The
new helper owns the inherited style invalidation behavior that follows
from language and directionality changes.