numastat.txt: standardize document format

Each text file under Documentation follows a different
format. Some doesn't even have titles!

Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:

- mark the document title;
- mark the table as such.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/numastat.txt

-
+===============================
 Numa policy hit/miss statistics
+===============================
 
 /sys/devices/system/node/node*/numastat
 
 All units are pages. Hugepages have separate counters.
 
+=============== ============================================================
 numa_hit	A process wanted to allocate memory from this node,
 		and succeeded.
 
@@ -20,6 +22,7 @@ other_node	A process ran on this node and got memory from another node.
 
 interleave_hit 	Interleaving wanted to allocate from this node
 		and succeeded.
+=============== ============================================================
 
 For easier reading you can use the numastat utility from the numactl package
 (http://oss.sgi.com/projects/libnuma/). Note that it only works