doc: fix compute API microversion list format

Change-Id: I5737b2c906b9e85e7cac3a3abd0746db608bc79d
diff --git a/doc/source/microversion_testing.rst b/doc/source/microversion_testing.rst
index 983fa24..4b1c145 100644
--- a/doc/source/microversion_testing.rst
+++ b/doc/source/microversion_testing.rst
@@ -338,8 +338,8 @@
 
   .. _2.26: https://docs.openstack.org/nova/latest/reference/api-microversion-history.html#id23
 
-* `2.28`_

-

+  * `2.28`_
+
   .. _2.28: https://docs.openstack.org/nova/latest/reference/api-microversion-history.html#id25
 
   * `2.32`_