Merge pull request opencontainers#117 from wking/runtime-headings

runtime-config-linux: Minor header cleanups after opencontainers#88

Author: LK4D4

runtime-config-linux.md

@@ -1,4 +1,4 @@
-## Linux namespaces
+## Namespaces
 
 A namespace wraps a global system resource in an abstraction that makes it 
 appear to the processes within the namespace that they have their own isolated 
@@ -127,11 +127,13 @@ Next parameters can be specified:
     ]
 ```
 
-## Linux control groups
+## Control groups
 
 Also known as cgroups, they are used to restrict resource usage for a container and handle
 device access.  cgroups provide controls to restrict cpu, memory, IO, and network for
-the container. For more information, see the [kernel cgroups documentation](https://www.kernel.org/doc/Documentation/cgroups/cgroups.txt)## Linux sysctl
+the container. For more information, see the [kernel cgroups documentation](https://www.kernel.org/doc/Documentation/cgroups/cgroups.txt).
+
+## Sysctl
 
 sysctl allows kernel parameters to be modified at runtime for the container.
 For more information, see [the man page](http://man7.org/linux/man-pages/man8/sysctl.8.html)
@@ -143,7 +145,7 @@ For more information, see [the man page](http://man7.org/linux/man-pages/man8/sy
    }
 ```
 
-## Linux rlimits
+## Rlimits
 
 ```json
    "rlimits": [