- Move all generator Lua scripts to the `src/gen/`
- Add a `.luarc.json` to `src/gen/`
- Add a `preload.lua` to `src/gen/`
  - Add `src` to `package.path` so it aligns with `.luarc.json'
- Fix all `require` statements in `src/gen/` so they are consistent:
    - `require('scripts.foo')` -> `require('gen.foo')`
    - `require('src.nvim.options')` -> `require('nvim.options')`
    - `require('api.dispatch_deprecated')` -> `require('nvim.api.dispatch_deprecated')`

Problem:
Generated Lua API bindings may have trailing spaces (e.g. nvim_set_hl).

Solution:
Add leading spaces only if arg_free_code is non-empty.
Also:
- Remove an unnecessary string.format() in write_shifted_output() args.
- Fix incorrect indent for the nlua_push_keydict() below.

vim-patch:partial:9.1.1084: Unable to persistently ignore events in a window and its buffers

Problem:  Unable to persistently ignore events in a window and its buffers.
Solution: Add 'eventignorewin' option to ignore events in a window and buffer
          (Luuk van Baal)

Add the window-local 'eventignorewin' option that is analogous to
'eventignore', but applies to a certain window and its buffers. Identify
events that should be allowed in 'eventignorewin', adapt "auto_event"
and "event_tab" to encode this information. Window context is not passed
onto apply_autocmds_group(), and when to ignore an event is a bit
ambiguous when "buf" is not "curbuf", rather than a large refactor, only
ignore an event when all windows into "buf" are ignoring the event.

https://github.com/vim/vim/commit/b7147f8236c962cd74d1ce028d9106f1c449ea6c

vim-patch:9.1.1102: tests: Test_WinScrolled_Resized_eiw() uses wrong filename

Problem:  tests: Test_WinScrolled_Resized_eiw() uses wrong filename
          (Luuk van Baal, after v9.1.1084)
Solution: Rename the filename to something more unique

https://github.com/vim/vim/commit/bfc7719e48ffc365ee0a1bd1888120d26b6365f0

* refactor(options): generic expand and did_set callbacks

Problem:

Many options have similar callbacks to check the values are valid.

Solution:

Generalize these callbacks into a single function that reads the option
table.

* refactor: gen_options.lua

refactor: gen_options.lua - inline get_cond

* refactor(options): use a simpler format for the common default

Problem: It was decided on Matrix chat that multitype options won't be necessary for Neovim options, and that options should only have a single canonical type. Therefore the code for supporting multitype options is unnecessary.

Solution: Remove the additional code that's used to provide multitype option support.

Always match ex-bang explicitly rather than incidentally as the ! operator.

fixes: vim/vim#16221
closes: vim/vim#16410

https://github.com/vim/vim/commit/1718e7d07e391571ac81c507a746b3bc7a7e2024

Co-authored-by: Doug Kearns <dougkearns@gmail.com>

Problem:
`termopen` has long been a superficial wrapper around `jobstart`, and
has no real purpose. Also, `vim.system` and `nvim_open_term` presumably
will replace all features of `jobstart` and `termopen`, so centralizing
the logic will help with that.

Solution:
- Introduce `eval/deprecated.c`, where all deprecated eval funcs will live.
- Introduce "term" flag of `jobstart`.
- Deprecate `termopen`.

Problem:  not possible to configure :messages
Solution: add the 'messagesopt' option (Shougo Matsushita)

closes: vim/vim#16068

https://github.com/vim/vim/commit/51d4d84d6a7159c6ce9e04b36f8edc105ca3794b

Co-authored-by: Shougo Matsushita <Shougo.Matsu@gmail.com>
Co-authored-by: h_east <h.east.727@gmail.com>

Problem:
- nvim_subscribe, nvim_unsubscribe were deprecated in
  aec4938a21a02d279d13a9eb64ef3b7cc592c374 but this wasn't set in the
  API metadata.
- The function annotations
  ```
  FUNC_API_SINCE(1) FUNC_API_REMOTE_ONLY FUNC_API_DEPRECATED_SINCE(13)
  ```
  cause this test to fail:
   ```
   RUN T3 api metadata functions are compatible with old metadata or have new level: 3.00 ms ERR
   test/functional/api/version_spec.lua:135: function vim_subscribe was removed but exists in level 0 which nvim should be compatible with
   stack traceback:
     test/functional/api/version_spec.lua:135: in function <test/functional/api/version_spec.lua:128>
   ```

Solution:
- Set the API metadata.
- Rearrange the annotations so that FUNC_API_DEPRECATED_SINCE is 2nd:
  ```
  FUNC_API_SINCE(1) FUNC_API_DEPRECATED_SINCE(13) FUNC_API_REMOTE_ONLY
  ```

Problem:
gen_declarations.lua is complex and has duplicate logic with
c_grammar.lua

Solution:
Move all lpeg logic to c_grammar.lua and refactor gen_declarations.lua.