docs: cgroup-v1: move hierarchy of accounting caption

The caption for hierarchy of accounting figure is in the code block,
which is quite odd. Move the caption into :caption: option of
code-block:: directive instead.

Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Documentation/admin-guide/cgroup-v1/memory.rst

@@ -147,7 +147,8 @@ specific data structure (mem_cgroup) associated with it.
 2.2. Accounting
 ---------------
 
-::
+.. code-block::
+   :caption: Figure 1: Hierarchy of Accounting
 
 		+--------------------+
 		|  mem_cgroup        |
@@ -167,7 +168,6 @@ specific data structure (mem_cgroup) associated with it.
            |               |           |               |
            +---------------+           +---------------+
 
-             (Figure 1: Hierarchy of Accounting)
 
 
 Figure 1 shows the important aspects of the controller