docs/specs/rocker.txt: Convert to rST

Convert the rocker.txt specification document to rST format.  We make
extensive use of the :: marker to introduce a literal block for all
the tables and ASCII art, rather than trying to convert the tables to
rST table syntax.  This produces a valid rST document without needing
a huge diff.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20240801170131.3977807-2-peter.maydell@linaro.org

MAINTAINERS

@@ -2465,7 +2465,7 @@ S: Maintained
 F: hw/net/rocker/
 F: qapi/rocker.json
 F: tests/rocker/
-F: docs/specs/rocker.txt
+F: docs/specs/rocker.rst
 
 e1000x
 M: Dmitry Fleytman <dmitry.fleytman@gmail.com>

docs/specs/index.rst

@@ -35,3 +35,4 @@ guest hardware that is specific to QEMU.
    vmcoreinfo
    vmgenid
    rapl-msr
+   rocker