PIR/PASM/PBC files without extensions

[Allison Randal]

Patrick R. Michaud wrote:
> 
> AFAIK, none of PGE, PCT, Rakudo, or any of the tools I'm working with
> expect to use load_bytecode without a file extension.  If they do,
> it wouldn't bother me to have them changed so that they don't.

Okay, I've added it to DEPRECATED.pod. Anyone who wants to keep the 
feature can make a case before the next release.

Allison