Improve GDB's first user experience by reducing "print_gdb_version" output

[Guinevere Larsen via Gdb <gdb@sourceware.org>]

Hi all,

I've been thinking about how to improve the user experience, especially 
for first time users. One thing that stands out to me is the very 
verbose first output a new user is greeted with:

GNU gdb (GDB) 17.0.50.20250526-git
Copyright (C) 2024 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later 
<http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Type "show copying" and "show warranty" for details.
This GDB was configured as "x86_64-pc-linux-gnu".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<https://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
     <http://www.gnu.org/software/gdb/documentation/>.

For help, type "help".
Type "apropos word" to search for commands related to "word".
(gdb)

For the *vast* majority of our users, only 4 of those lines are useful 
at all: the GDB version (to ask for help), where to find the 
documentation, the "help" command, and the "apropos" command. Arguably, 
where to report bugs could be useful, but the worst ones already print 
it and otherwise users are incredibly unlikely to report them 
(especially given the email requirements to create an account). Worthy 
of note, the important lines are the last ones, so even if a new user 
was eager enough to start reading everything, they'd likely gloss over 
everything assuming this entire thing is just copyright.

I propose that the text be updated to something similar to this:

GNU gdb (GDB) 17.0.50.20250526-git
For a list of commands, use "help"
For all commands related to a certain word, use "apropos word"
For a thorough explanation of what GDB can do, check the manual at:
     <http://www.gnu.org/software/gdb/documentation/>
For information on GDB's copyright, warranty or configuration, use
     "show copying/warranty/configuration"
(gdb)

This makes the text smaller, the start is more focused on what most 
users will be interested in, and keeps all the very relevant information 
still available for those interested.

I'm sending this here in case there is some rule that forces us to write 
the copyright or free software status at initialization, before spending 
the time to turn this into a patch.

-- 
Cheers,
Guinevere Larsen
She/Her/Hers