Problem:
checkhealth can be noisy, but we don't want to omit info.

Solution:
Fold OK results by default, if 'foldenable' is enabled.
Resolves #22796

The following functions are deprecated and will be removed in
Nvim v0.11:

- health#report_start()
- health#report_info()
- health#report_ok()
- health#report_warn()
- health#report_error()
- vim.health.report_start()
- vim.health.report_info()
- vim.health.report_ok()
- vim.health.report_warn()
- vim.health.report_error()

Users should instead use these:

- vim.health.start()
- vim.health.info()
- vim.health.ok()
- vim.health.warn()
- vim.health.error()

* refactor: remove all vimscript from nvim/health
* fixup: previous method broke if you had a folder named 'x-lua'

Problem:
https://github.com/neovim/neovim/pull/18720#issuecomment-1142614996

The vim.health module is detected as a healthcheck, which produces spurious errors:

    vim: require("vim.health").check()
    ========================================================================
    - ERROR: Failed to run healthcheck for "vim" plugin. Exception:
      function health#check, line 20
      Vim(eval):E5108: Error executing lua [string "luaeval()"]:1: attempt to call field 'check' (a nil value)
      stack traceback:
      [string "luaeval()"]:1: in main chunk

Solution:
Skip vim.health when discovering healthchecks.

- Complete function:
  There was lots of unnecessary C code for the complete function, therefore
  moving it to Lua and use all the plumbing we have in place to retrieve the
  results.
- Moving the module:
  It's important we keep nvim lua modules name spaced, avoids conflict with
  plugins, luarocks, etc.