[gdb] Fix maint print symbols/psymbols help text

[gdb] Fix maint print symbols/psymbols help text

Consider the help text of "maint print symbols":
...
(gdb) help maint print symbols
Print dump of current symbol definitions.
Usage: mt print symbols [-pc ADDRESS] [--] [OUTFILE]
       mt print symbols [-objfile OBJFILE] [-source SOURCE] [--] [OUTFILE]
Entries in the full symbol table are dumped to file OUTFILE,
or the terminal if OUTFILE is unspecified.
If ADDRESS is provided, dump only the file for that address.
If SOURCE is provided, dump only that file's symbols.
If OBJFILE is provided, dump only that file's minimal symbols.
...
and "maint print psymbols":
...
(gdb) help maint print psymbols
Print dump of current partial symbol definitions.
Usage: mt print psymbols [-objfile OBJFILE] [-pc ADDRESS] [--] [OUTFILE]
       mt print psymbols [-objfile OBJFILE] [-source SOURCE] [--] [OUTFILE]
Entries in the partial symbol table are dumped to file OUTFILE,
or the terminal if OUTFILE is unspecified.
If ADDRESS is provided, dump only the file for that address.
If SOURCE is provided, dump only that file's symbols.
If OBJFILE is provided, dump only that file's minimal symbols.
...

The OBJFILE lines mistakingly mention minimal symbols.

Fix this by reformulating as "dump only that object file's symbols".

Also make the ADDRESS lines more clear by using the formulation: "dump only
the symbols for the file with code at that address".

Tested on x86_64-linux.

Co-Authored-By: Eli Zaretskii <eliz@gnu.org>
PR gdb/30742
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30742