This reduces the number of `.cpp` files that need to be recompiled when
one of the below header files changes as follows:
Painting/Command.h: 1030 -> 61
Painting/DisplayList.h: 1030 -> 60
Painting/DisplayListRecorder.h: 557 -> 59
We've long claimed to support this, but then silently ignored string
values, until 4cb2063577 which would
not-so-silently crash instead. (Oops)
So, actually pass the string value along and use it in the list marker.
As part of this, rename our `list-style-type` enum to
`counter-style-name-keyword`. This is an awkward name, attempting to be
spec-based. (The spec says `<counter-style>`, which is either a
`<counter-style-name>` or a function, and the `<counter-style-name>` is
a `<custom-ident>` that also has a few predefined values. So this is the
best I could come up with.)
Unfortunately only one WPT test for this passes - the others fail
because we produce a different layout when text is in `::before` than
when it's in `::marker`, and similar issues.
Resulting in a massive rename across almost everywhere! Alongside the
namespace change, we now have the following names:
* JS::NonnullGCPtr -> GC::Ref
* JS::GCPtr -> GC::Ptr
* JS::HeapFunction -> GC::Function
* JS::CellImpl -> GC::Cell
* JS::Handle -> GC::Root
Now that the heap has no knowledge about a JavaScript realm and is
purely for managing the memory of the heap, it does not make sense
to name this function to say that it is a non-realm variant.
