feat(treesitter): improved logging (#23638)

- Add bindings to Treesitter ts_parser_set_logger and ts_parser_logger
- Add logfile with path STDPATH('log')/treesitter.c
- Rework existing LanguageTree loggin to use logfile
- Begin implementing log levels for vim.g.__ts_debug

runtime/lua/vim/fs.lua

@@ -73,10 +73,14 @@ function M.basename(file)
 end
 
 ---@private
-local function join_paths(...)
+---@param ... string
+---@return string
+function M._join_paths(...)
   return (table.concat({ ... }, '/'):gsub('//+', '/'))
 end
 
+local join_paths = M._join_paths
+
 ---@alias Iterator fun(): string?, string?
 
 --- Return an iterator over the files and directories located in {path}