docs: netlink: netlink-raw.rst: use :ref: instead of :doc:

Currently, rt documents are referred with:

Documentation/userspace-api/netlink/netlink-raw.rst: :doc:`rt-link<../../networking/netlink_spec/rt-link>`
Documentation/userspace-api/netlink/netlink-raw.rst: :doc:`tc<../../networking/netlink_spec/tc>`
Documentation/userspace-api/netlink/netlink-raw.rst: :doc:`tc<../../networking/netlink_spec/tc>`

Having :doc: references with relative paths doesn't always work,
as it may have troubles when O= is used. Also that's hard to
maintain, and may break if we change the way rst files are
generated from yaml. Better to use instead a reference for
the netlink family.

So, replace them by Sphinx cross-reference tag that are
created by ynl_gen_rst.py.

Signed-off-by: Mauro Carvalho Chehab <[e-mail]>
Reviewed-by: Donald Hunter <[e-mail]>

Documentation/userspace-api/netlink/netlink-raw.rst

···
 ------------
 
 Several raw netlink families such as
-:doc:`rt-link<../../networking/netlink_spec/rt-link>` and
-:doc:`tc<../../networking/netlink_spec/tc>` use attribute nesting as an
+:ref:`rt-link<netlink-rt-link>` and
+:ref:`tc<netlink-tc>` use attribute nesting as an
 abstraction to carry module specific information.
 
 Conceptually it looks as follows::
···
 Nested struct definitions
 -------------------------
 
-Many raw netlink families such as :doc:`tc<../../networking/netlink_spec/tc>`
+Many raw netlink families such as :ref:`tc<netlink-tc>`
 make use of nested struct definitions. The ``netlink-raw`` schema makes it
 possible to embed a struct within a struct definition using the ``struct``
 property. For example, the following struct definition embeds the

tools/net/ynl/pyynl/ynl_gen_rst.py

···
 
     # Main header
 
-    lines.append(rst_header())
-
     family = obj['name']
+
+    lines.append(rst_header())
+    lines.append(rst_label("netlink-" + family))
 
     title = f"Family ``{family}`` netlink specification"
     lines.append(rst_title(title))