[Docs] Metadata interceptor example have `on_end` signature wrong

[valentimarco]

The example in the docs have on_end method signature wrong. Here the correct example:

from contextvars import ContextVar, Token

from connectrpc.code import Code
from connectrpc.errors import ConnectError
from connectrpc.request import RequestContext

_auth_token = ContextVar["auth_token"]("current_auth_token")

class ServerAuthInterceptor:
    def __init__(self, valid_tokens: list[str]):
        self._valid_tokens = valid_tokens

    async def on_start(self, ctx: RequestContext) -> Token["auth_token"]:
        authorization = ctx.request_headers().get("authorization")
        if not authorization or not authorization.startswith("Bearer "):
            raise ConnectError(Code.UNAUTHENTICATED, message="")
        token = authorization[len("Bearer ") :]
        if token not in self._valid_tokens:
            raise ConnectError(Code.PERMISSION_DENIED, message="")
        return _auth_token.set(token)

    async def on_end(
        self, token: Token["auth_token"], ctx: RequestContext, error: Exception | None
    ):
        _auth_token.reset(token)

[stefanvanburen]

Hi @valentimarco, thanks for the report - sent connectrpc/connectrpc.com#343 to fix.