docs: changes/ver_linux: fix entries and add several tools

docs: changes/ver_linux: fix entries and add several tools

Some of the entries in both Documentation/process/changes.rst and
script/ver_linux were obsolete; update them to reflect the current way of
getting version information.

Many were missing altogether; add the relevant information for:

 bash, bc, bindgen, btrfs-progs, Clang, gdb,  GNU awk, GNU tar,
 GRUB, GRUB2, gtags, iptables, kmod, mcelog, mkimage, openssl,
 pahole, Python, Rust, Sphinx, squashfs-tools

Signed-off-by: Manuel Ebner <manuelebner@mailbox.org>
[jc: rewrote changelog]
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20260325194616.78093-2-manuelebner@mailbox.org>