Allow for chained calls

[JoshuaKGoldberg]

This gives an invalid syntax complaint:

/**
 * Starts a foreach loop over a container's keys.
 */
export class ForEachKeyStartCommand extends Command {
    /**
     * Metadata on the command.
     */
    private static metadata: CommandMetadata = new CommandMetadata(CommandNames.ForEachKeyStart)
        .withDescription("Starts a foreach loop over a container's keys.")
        .withIndentation([1])
        .withParameters([
            new SingleParameter("container", "A container to iterate over.", true),
            new SingleParameter("keyName", "The name of the iteration key variable.", true),
            new SingleParameter("keyType", "The type of the iteration key variable.", true)
        ]);
}

[JoshuaKGoldberg]

Done :)