[fpc-pascal] The names of the various FPC documentation

[Marco van de Voort]

In our previous episode, Michael Van Canneyt said:
> > Yes I know I can rename them locally, but I also thing it makes sense to
> > give the documents better "default" names than ref, prog, user.
> 
> If there is a more or less consensus about such things, I don't see why
> we couldn't rename them.

If you do, don't forget to update fpcdocs/gentoc :-)

Still, short names for the files themselves would be better I think.