[RFA/doco] document gdb.init check only performed in home directory

[Eli Zaretskii]

> From: Joel Brobecker <brobecker@adacore.com>
> Cc: Joel Brobecker <brobecker@adacore.com>
> Date: Thu,  8 Nov 2012 13:56:07 -0800
> 
> gdb/doc/ChangeLog:
> 
>         * gdb.texinfo (Startup): Clarify scope of gdb.ini warning for
>         Windows ports.
> 
> Tested on x86_64-linux. OK to apply?

Yes, thanks.  However, I would suggest to lose the plural form, and
just use "The Windows port" in singular.  A GDB user who uses GDB on
Windows only cares about that one port she is using.