stdlib: Use pos-only parameters for many Protocols (#10985)

stdlib/email/headerregistry.pyi

@@ -143,9 +143,9 @@ if sys.version_info >= (3, 8):
 class _HeaderParser(Protocol):
     max_count: ClassVar[Literal[1] | None]
     @staticmethod
-    def value_parser(value: str) -> TokenList: ...
+    def value_parser(__value: str) -> TokenList: ...
     @classmethod
-    def parse(cls, value: str, kwds: dict[str, Any]) -> None: ...
+    def parse(cls, __value: str, __kwds: dict[str, Any]) -> None: ...
 
 class HeaderRegistry:
     registry: dict[str, type[_HeaderParser]]