Fix command escaping to match runner

[ericsciple]

The toolkit uses the new command syntax (::command::), yet the old escaping rules (for ##[command]).

The escaping rules are:

        private static readonly EscapeMapping[] _escapeDataMappings = new[]
        {
            new EscapeMapping(token: "\r", replacement: "%0D"),
            new EscapeMapping(token: "\n", replacement: "%0A"),
            new EscapeMapping(token: "%", replacement: "%25"),
        };

        private static readonly EscapeMapping[] _escapePropertyMappings = new[]
        {
            new EscapeMapping(token: "\r", replacement: "%0D"),
            new EscapeMapping(token: "\n", replacement: "%0A"),
            new EscapeMapping(token: ":", replacement: "%3A"),
            new EscapeMapping(token: ",", replacement: "%2C"),
            new EscapeMapping(token: "%", replacement: "%25"),
        };