/// Json format used by zigdoc
/// Start and end can be assumed to be offsets into "decls"
/// AD: { "dc": "doc comment", "pl": "pay_load", "sub_cont_type": "sub_container_type or undefined", "md": MD }
/// MD: { "fields": [start, end], "types": [start, end], "funcs": [start, end], "values": [start, end]}
/// {
///     "fields": [start, end],
///     "types": [start, end],
///     "funcs": [start, end],
///     "values": [start, end],
///     "decls": [AD],
/// }
///