Problem:
- `vim.json` exposes various global options which:
- affect all Nvim Lua plugins (especially the LSP client)
- are undocumented and untested
- can cause confusing problems such as: cc76ae3abe
- `vim.json` exposes redundant mechanisms:
- `vim.json.null` is redundant with `vim.NIL`.
- `array_mt` is redundant because Nvim uses a metatable
(`vim.empty_dict()`) for empty dict instead, which `vim.json` is
configured to use by default (see `as_empty_dict`).
Example:
```
:lua vim.print(vim.json.decode('{"bar":[],"foo":{}}'))
--> { bar = {}, foo = vim.empty_dict() }
```
Thus we don't need to also decorate empty arrays with `array_mt`.
Solution:
Remove the functions from the public vim.json interface.
Comment-out the implementation code to minimize drift from upstream.
TODO:
- Expose the options as arguments to `vim.json.new()`
8d4a53fe6e