Here I try to address bug where content of table overflows
it's width (hacker news is an example of such site) by
reimplementing some parts of table formatting context.
Now TFC implements first steps of:
https://www.w3.org/TR/css-tables-3/#table-layout-algorithm
but column width and row height distribution steps are
still very incomplete.
This removes a set of complex reference cycles between DOM, layout tree
and browsing context.
It also makes lifetimes much easier to reason about, as the DOM and
layout trees are now free to keep each other alive.
This means we can instantiate them for pseudo-elements, which don't have
an associated Element. They all pass it to their parent as a
`Layout::Node*` and handle a lack of `layout_node()` already so this
won't affect any functionality.
There's a subtle difference here. A "block box" in the spec is a
block-level box, while a "block container" is a box whose children are
either all inline-level boxes in an IFC, or all block-level boxes
participating in a BFC.
Notably, an "inline-block" box is a "block container" but not a "block
box" since it is itself inline-level.
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
