feat(tmux)!: update parser and highlights

Breaking changes:

- Node `(variable)` was renamed to `(expr_double_quotes)`.
- Node `(variable_raw)` was renamed to `(expr_single_quotes)`.
- Node `(string)` was renamed to `(str_double_quotes)`.
- Node `(raw_string)` was renamed to `(str_single_quotes)`.
- Node `(raw_string_quote)` was removed.

lua/nvim-treesitter/parsers.lua

@@ -2372,10 +2372,10 @@ return {
   },
   tmux = {
     install_info = {
-      revision = '0252ecd080016e45e6305ef1a943388f5ae2f4b4',
+      revision = 'a2936cb2579f7723b5744563c45bcefabc42fe47',
       url = 'https://github.com/Freed-Wu/tree-sitter-tmux',
     },
-    maintainers = { '@Freed-Wu' },
+    maintainers = { '@Freed-Wu', '@stevenxxiu' },
     tier = 2,
   },
   todotxt = {