docs: Replace dangling references to docs/interop/qmp-intro.txt

Deletion of docs/interop/qmp-intro.txt left two dangling references
behind.  Replace them by references to docs/interop/qmp-spec.rst.

Fixes: 0ec4468f23 (docs/interop: Delete qmp-intro.txt)
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240120095327.666239-3-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>

docs/devel/writing-monitor-commands.rst

@@ -8,8 +8,8 @@ This document doesn't discuss QMP protocol level details, nor does it dive
 into the QAPI framework implementation.
 
 For an in-depth introduction to the QAPI framework, please refer to
-docs/devel/qapi-code-gen.txt. For documentation about the QMP protocol,
-start with docs/interop/qmp-intro.txt.
+docs/devel/qapi-code-gen.txt.  For the QMP protocol, see the
+:doc:`/interop/qmp-spec`.
 
 New commands may be implemented in QMP only.  New HMP commands should be
 implemented on top of QMP.  The typical HMP command wraps around an

docs/interop/bitmaps.rst

@@ -166,9 +166,9 @@ Basic QMP Usage
 ---------------
 
 The primary interface to manipulating bitmap objects is via the QMP
-interface. If you are not familiar, see docs/interop/qmp-intro.txt for a broad
-overview, and `qemu-qmp-ref <qemu-qmp-ref.html>`_ for a full reference of all
-QMP commands.
+interface. If you are not familiar, see the :doc:`qmp-spec` for the
+protocol, and `qemu-qmp-ref <qemu-qmp-ref.html>`_ for a full
+reference of all QMP commands.
 
 Supported Commands
 ~~~~~~~~~~~~~~~~~~