qapi/block-core: Fix BlockLatencyHistogramInfo doc markup

The description of @bins ends with a literal block:

    # @bins: list of io request counts corresponding to histogram
    #     intervals, one more element than @boundaries has.  For the
    #     example above, @bins may be something like [3, 1, 5, 2], and
    #     corresponding histogram looks like:
    #
    # ::
    #
    #        5|           *

Except it actually ends *before* the block: the unindented '::' line
starts a new section.  Makes no sense.

We could fix this by indenting the '::' line.  Instead, double the
colon at the end of the preceding paragraph, and drop the '::' line.

This shifts the box for the literal block right in generated
documentation, so it lines up with the description.

Fixes: commit a0fcff3 (qapi: Use rST markup for literal blocks)
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240205074709.3613229-4-armbru@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

qapi/block-core.json

@@ -656,9 +656,7 @@
 # @bins: list of io request counts corresponding to histogram
 #     intervals, one more element than @boundaries has.  For the
 #     example above, @bins may be something like [3, 1, 5, 2], and
-#     corresponding histogram looks like:
-#
-# ::
+#     corresponding histogram looks like::
 #
 #        5|           *
 #        4|           *