Merge branch 'ynl-avoid-leaks-in-attr-override-and-spec-fixes-for-c'

Jakub Kicinski says:

====================
ynl: avoid leaks in attr override and spec fixes for C

The C rt-link work revealed more problems in existing codegen
and classic netlink specs.

Patches 1 - 4 fix issues with the codegen. Patches 1 and 2 are
pre-requisites for patch 3. Patch 3 fixes leaking memory if user
tries to override already set attr. Patch 4 validates attrs in case
kernel sends something we don't expect.

Remaining patches fix and align the specs. Patch 5 changes nesting,
the rest are naming adjustments.
====================

Link: https://patch.msgid.link/20250414211851.602096-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>