doc/hacking.txt: Point to the ELinks-specific po/perl/README, rather
than to the generic po/perl/check-accelerator-conflicts.pl.
po/perl/README: Removed a spurious preposition.
The detailed documentation is now as POD in the scripts, and the README
just gives an overview and describes how the scripts relate to ELinks.
The intention here is to make the scripts more readily usable for programs
other than ELinks. The scripts now describe their licensing, too.
