Use modern typehint syntax

tools/copy_init_imports.py

@@ -7,12 +7,11 @@ import ast
 import os
 import re
 from pathlib import Path
-from typing import List
 
 
 class ImportVisitor(ast.NodeVisitor):
     def __init__(self) -> None:
-        self.imported_names: List[str] = []
+        self.imported_names: list[str] = []
 
     def visit_ImportFrom(self, node: ast.ImportFrom) -> None:
         if node.level == 1:
@@ -26,7 +25,7 @@ def main() -> None:
         rf"(tl|mtproto){re.escape(os.path.sep)}(abcs|functions|types)"
     )
 
-    files: List[str] = []
+    files: list[str] = []
     for file in impl_root.rglob("__init__.py"):
         file_str = str(file)
         if autogenerated_re.search(file_str):