PR format for ChangeLog entries

[Andrew Cagney]

> For what it's worth, I've noticed that, if a bug is, say, a C++ bug,
> then GNATS picks up on ChangeLog entries that reference PR c++/###,
> not PR gdb/###.  Perhaps GNATS should be fixed to notice both sorts of
> entries, but for now it might be wise to mention the specific category
> in ChangeLog entries, even though we've decided we're sticking with
> gdb/### for KFAIL entries in the testsuite.
> 
> (I _could_ be wrong about GNATS' behaviour: I know it picks up on
> PR c++/###, and I think that I've seen it not notice PR gdb/###.)

This needs to be fixed.  Doing things one way in one place, and a second 
in a second place will just confuse people (and re-start old debates :-)

Andrew