* docs: drop "lua-" prefix from most treesitter tags
* docs: move mouse section from tui.txt to gui.txt
* docs: misc

Design goals/requirements:
- Default configuration of a server can be distributed across multiple sources.
  - And via RTP discovery.
- Default configuration can be specified for all servers.
- Configuration _can_ be project specific.

Solution:

- Two new API's:
  - `vim.lsp.config(name, cfg)`:
    - Used to define default configurations for servers of name.
    - Can be used like a table or called as a function.
    - Use `vim.lsp.confg('*', cfg)` to specify default config for all
      servers.
  - `vim.lsp.enable(name)`
    - Used to enable servers of name. Uses configuration defined
    via `vim.lsp.config()`.

* refactor(shared): extract `vim._list_insert` and `vim._list_remove`

* feat(lsp): add `vim.lsp.foldexpr()`

* docs(lsp): add a todo for state management

* feat(lsp): add `vim.lsp.folding_range.foldclose()`

* feat(lsp): schedule `foldclose()` if the buffer is not up-to-date

* feat(lsp): add `vim.lsp.foldtext()`

* feat(lsp): support multiple folding range providers

* refactor(lsp): expose all folding related functions under `vim.lsp.*`

* perf(lsp): add `lsp.MultiHandler` for do `foldupdate()` only once

Deprecated:
- `client.request()` -> `client:request()`
- `client.request_sync()` -> `client:request_sync()`
- `client.notify()` -> `client:notify()`
- `client.cancel_request()` -> `client:cancel_request()`
- `client.stop()` -> `client:stop()`
- `client.is_stopped()` `client:is_stopped()`
- `client.supports_method()` -> `client:supports_method()`
- `client.on_attach()` -> `client:on_attach()`

Fixed docgen to link class fields to the full function doc.

Problem:
- `vim.highlight` module does not follow `:help dev-name-common`, which
  documents the name for "highlight" as "hl".
- Shorter names are usually preferred.

Solution:
Rename `vim.highlight` to `vim.hl`.

This is not a breaking change until 2.0 (or maybe never).

An implication of this current approach is that `NVIM_API_LEVEL` should be
bumped when a new Lua function is added.

TODO(future): add a lint check which requires `@since` on all new functions.

ref #25416

**Problem:** The documentation for `TSNode` and `TSTree` methods is
incomplete from the LSP perspective. This is because they are written
directly to the vimdoc, rather than in Lua and generated to vimdoc.

**Solution:** Migrate the docs to Lua and generate them into the vimdoc.
This requires breaking up the `treesitter/_meta.lua` file into a
directory with a few different modules.

This commit also makes the vimdoc generator slightly more robust with
regard to sections that have multiple help tags (e.g. `*one* *two*`)