doc: netlink: Don't 'sanitize' op docstrings in generated .rst

doc: netlink: Don't 'sanitize' op docstrings in generated .rst

The doc strings for do/dump ops are emitted as toplevel .rst constructs
so they can be multi-line. Pass multi-line text straight through to the
.rst to retain any simple formatting from the .yaml

This fixes e.g. list formatting for the pin-get docs in dpll.yaml:

https://docs.kernel.org/6.9/networking/netlink_spec/dpll.html#pin-get

Signed-off-by: Donald Hunter <donald.hunter@gmail.com>
Link: https://lore.kernel.org/r/20240528140652.9445-3-donald.hunter@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>