Previously we were inconsistent by generating code for enum definitions
but not generating code for dictionaries. With future changes to the
IDL generator to expose helpers to convert to and from IDL values
this produced circular depdendencies. To solve this problem, also
generate the dictionary definitions in bindings headers.
Generate exact JS buffer types for exact IDL buffer arguments instead
of widening them to BufferSource or ArrayBufferView.
This fixes cases like TextEncoder.encodeInto(), whose IDL requires
a Uint8Array destination. Previously the generated binding accepted
any BufferSource, so DataView, other typed arrays, and
ArrayBuffer-backed values were let through. With exact conversion,
those are rejected at the binding layer as expected.
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
