docs: networking: convert rds.txt to ReST

- add SPDX header;
- add a document title;
- mark code blocks and literals as such;
- mark tables as such;
- mark lists as such;
- adjust identation, whitespaces and blank lines where needed;
- add to networking/index.rst.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/networking/index.rst

@@ -97,6 +97,7 @@ Contents:
    proc_net_tcp
    radiotap-headers
    ray_cs
+   rds
 
 .. only::  subproject and html
 

MAINTAINERS

@@ -14219,7 +14219,7 @@ L:	linux-rdma@vger.kernel.org
 L:	rds-devel@oss.oracle.com (moderated for non-subscribers)
 S:	Supported
 W:	https://oss.oracle.com/projects/rds/
-F:	Documentation/networking/rds.txt
+F:	Documentation/networking/rds.rst
 F:	net/rds/
 
 RDT - RESOURCE ALLOCATION