Remove Python 3.6 branches from typeshed (#8269)

stubs/html5lib/html5lib/_tokenizer.pyi

@@ -1,13 +1,8 @@
-import sys
-from collections import OrderedDict
 from typing import Any
 from typing_extensions import TypeAlias
 
 entitiesTrie: Any
-if sys.version_info >= (3, 7):
-    attributeMap: TypeAlias = dict[Any, Any]
-else:
-    attributeMap: TypeAlias = OrderedDict[Any, Any]
+attributeMap: TypeAlias = dict[Any, Any]
 
 class HTMLTokenizer:
     stream: Any