bug: treesitter markdown highlight error if no parser is found

[SilverMira]

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• I have read all the noice.nvim docs
• I have searched the existing issues of noice.nvim
• I have searched the exsiting issues of plugins related to this issue

Neovim version (nvim -v)

v0.9.0-dev-1175+g89a525de9

Operating system/version

Windows

Describe the bug

Encountered this issue while I'm writing some Dart code, which does have a Treesitter parser, but has an issue in which the parser falls into an infinite loop and freezes Neovim, which had me uninstall it. The following error is thrown if I open any nvim-cmp suggestion that has documentation, spamming the notifications.

Stacktrace

Error executing vim.schedule lua callback: ...eovim/share/nvim/runtime/lua/vim/treesitter/language.lua:87: no parser for 'dart' language, see :help treesitter-parsers
stack traceback:
	[C]: in function 'error'
	...eovim/share/nvim/runtime/lua/vim/treesitter/language.lua:87: in function 'add'
	...m/share/nvim/runtime/lua/vim/treesitter/languagetree.lua:87: in function 'new'
	.../nvim-data/lazy/noice.nvim/lua/noice/text/treesitter.lua:48: in function 'highlight'
	.../Local/nvim-data/lazy/noice.nvim/lua/noice/text/init.lua:67: in function 'highlight'
	...Data/Local/nvim-data/lazy/nui.nvim/lua/nui/line/init.lua:55: in function 'highlight'
	...Data/Local/nvim-data/lazy/nui.nvim/lua/nui/line/init.lua:70: in function 'render'
	...Local/nvim-data/lazy/noice.nvim/lua/noice/text/block.lua:97: in function 'render'
	...cal/nvim-data/lazy/noice.nvim/lua/noice/lsp/override.lua:38: in function 'stylize_markdown'
	...Local/nvim-data/lazy/nvim-cmp/lua/cmp/view/docs_view.lua:54: in function 'open'
	...a/AppData/Local/nvim-data/lazy/nvim-cmp/lua/cmp/view.lua:238: in function 'callback'
	...ta/Local/nvim-data/lazy/nvim-cmp/lua/cmp/utils/async.lua:111: in function 'cb'
	vim/_editor.lua:263: in function <vim/_editor.lua:262>

Additionally, whatever builtin highlight without depending on treesitter on nvim-cmp's window is removed

Using noice without treesitter parser

Not using noice, without treesitter parser

Steps To Reproduce

1. Uninstall a treesitter parser
2. Open the filetype for the unavailable parser
3. Have nvim-cmp suggest something

Expected Behavior

Noice should handle the case when no treesitter parser is available, and ideally fallback to the default highlighting

Repro

-- DO NOT change the paths and don't remove the colorscheme
local root = vim.fn.fnamemodify("./.repro", ":p")
-- set stdpaths to use .repro
for _, name in ipairs({ "config", "data", "state", "cache" }) do
  vim.env[("XDG_%s_HOME"):format(name:upper())] = root .. "/" .. name
end

-- bootstrap lazy
local lazypath = root .. "/plugins/lazy.nvim"
if not vim.loop.fs_stat(lazypath) then
  vim.fn.system({ "git", "clone", "--filter=blob:none", "https://github.com/folke/lazy.nvim.git", lazypath, })
end
vim.opt.runtimepath:prepend(lazypath)

-- install plugins
local plugins = {
  "folke/tokyonight.nvim",
  "folke/noice.nvim",
  -- add any other plugins here
}
require("lazy").setup(plugins, {
  root = root .. "/plugins",
})

vim.cmd.colorscheme("tokyonight")
-- add anything else here