It would be nice if `PromptRequiredError` already had the suggestions for the prompt

[Gnuxie]

  it("Will prompt for the policy list when it is missing", async function () {
    const { protectedRoomsSet, policyRoomManager } = await createProtectedRooms();
    const banResult = await CommandExecutorHelper.parseAndInvoke(
      DraupnirBanCommand,
      {
        policyRoomManager,
        roomResolver,
        issuerManager: protectedRoomsSet.issuerManager,
        defaultReasons: ["spam"],
        clientUserID: `@draupnir:ourserver.example.com` as StringUserID,
      },
      {},
      MatrixUserIDPresentationType.wrap(MatrixUserID.fromUserID("@spam:spam.example.com" as StringUserID)),
      undefined, // no policy room provided, we expect a prompt.
    );
    if (isOk(banResult)) {
      throw new TypeError(`We expect a prompt error to be returned`);
    }
    if (!(banResult.error instanceof PromptRequiredError)) {
      throw new TypeError(`Expected to have a prompt required error`)
    }
    expect(banResult.error.parameterRequiringPrompt.name).toBe("list");
  });

Would mean a test like this could also test that the prompt had been called properly.

[Gnuxie]

Ok, it turns out that we need to do this now anyways, because stream.isPromptable() will never work as we keep recreating streams out of thin air in the parsing code.

We will call the prompt whenever one is available and show the suggestions in the error message, much like the An argument for the parameter ${parameter.name} was expected but was not provided.

[Gnuxie]

Ok, the problem with doing that is it means we would have to pass the executor context all the way through to the parsing code which will be ugly. So I think we just change to PromptRequiredError by default and then something else can call them later.