nlohmann_json.natvis had no entries for the view and document types, so a
debugger showed the raw node index. Add visualizers for
basic_json_document<*,*>, basic_json_view<*,*> and detail::view::node.
A document is a flat index into the source text, so the strings of the
direct children can be read through document_data::base, while the
children of nested containers are shown as nodes (kind, size, numbers;
strings only by length). Containers with edits (node_flags::moved) are
not expanded. The types live in the same inline namespaces as basic_json
and view_mode is covered by a wildcard, so the ABI tags do not multiply
with it; the file grows from 862 KB to 1.7 MB.
Also correct the ABI tag count (11) in the --all size note.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>