docs/interop: Convert qmp-spec.txt to rST

Convert the qmp-spec.txt document to restructuredText.
Notable points about the conversion:
 * numbers at the start of section headings are removed, to match
   the style of the rest of the manual
 * cross-references to other sections or documents are hyperlinked
 * various formatting tweaks (notably the examples, which need the
   -> and <- prefixed so the QMP code-block lexer will accept them)
 * English prose fixed in a few places

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20230515162245.3964307-2-peter.maydell@linaro.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
[.. code-block:: dumbed down to :: to work around CI failure]

1 files changed, 2 insertions, 1 deletions

diff --git a/docs/devel/qapi-code-gen.rst b/docs/devel/qapi-code-gen.rst
index 5618a80378..7f78183cd4 100644
--- a/docs/devel/qapi-code-gen.rst
+++ b/docs/devel/qapi-code-gen.rst
@@ -545,7 +545,8 @@ Member 'allow-oob' declares whether the command supports out-of-band
  { 'command': 'migrate_recover',
    'data': { 'uri': 'str' }, 'allow-oob': true }
 
-See qmp-spec.txt for out-of-band execution syntax and semantics.
+See the :doc:`/interop/qmp-spec` for out-of-band execution syntax
+and semantics.
 
 Commands supporting out-of-band execution can still be executed
 in-band.