docs/devel/blkdebug: Convert to rST format

Convert blkdebug.txt to rST format.  We put it into index-build.rst
because it falls under the "test" part of "QEMU Build and Test
System".

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-id: 20240816132212.3602106-2-peter.maydell@linaro.org
diff --git a/MAINTAINERS b/MAINTAINERS
index 5cd661c..d4eb221 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3967,6 +3967,7 @@
 L: qemu-block@nongnu.org
 S: Supported
 F: block/blkdebug.c
+F: docs/devel/blkdebug.rst
 
 vpc
 M: Kevin Wolf <kwolf@redhat.com>