[openssl/openssl] aac139: Clarify dashes are required for openssl list command

[crox]

  Branch: refs/heads/openssl-3.0
  Home:   https://github.com/openssl/openssl
  Commit: aac139414e6f8fdfb4509f40811f1771f3ec193d
      https://github.com/openssl/openssl/commit/aac139414e6f8fdfb4509f40811f1771f3ec193d
  Author: Jeff Croxell <jcroxell at gmail.com>
  Date:   2022-08-22 (Mon, 22 Aug 2022)

  Changed paths:
    M doc/man1/openssl.pod

  Log Message:
  -----------
  Clarify dashes are required for openssl list command

Fixes #19013

CLA: trivial

Reviewed-by: Matt Caswell <matt at openssl.org>
Reviewed-by: Paul Dale <pauli at openssl.org>
(Merged from https://github.com/openssl/openssl/pull/19031)

(cherry picked from commit 63b94b3fc7feb12713fa46d386e10d109f074d28)