Delete abortion joke

[Florian Weimer]

* Javiera Serrano Polo:

> --- a/manual/startup.texi	2018-05-06 05:58:31.000000000 +0200
> +++ b/manual/startup.texi	2018-05-06 06:02:43.000000000 +0200
> @@ -1005,6 +1005,14 @@
>  intercept this signal; see @ref{Signal Handling}.
>  @end deftypefun
>  
> +@c Requested by rms.  Don't remove.
> +@cartouche
> +@strong{RMS Warning:} Proposed Federal censorship regulations

You should spell out the abbreviation.  It is ambiguous in a medical
context.

> +may prohibit us from giving you information about the possibility of
> +calling this function.  We would be required to say that this is not an
> +acceptable way of terminating a program.
> +@end cartouche

I still don't think this is appropriate, and I don't think it should
be added back.