Use div for code block so vue interpolation works

vuepress adds a `v:pre` tag to a fenced code block, which escapes
any vue interpolation so you see the full, unaffected code. this
interferes with instances where you need the vue interpolation for the
code to make sense. I updated an escaped code block to use the same
style as a block earlier in the snippet so that interpolation works.

see vuejs/vuepress#413

Author: zachmandeville

docs/.vuepress/_snippets/install_os.md

@@ -32,10 +32,9 @@ You can start the control-plane with: `kuma-{{ $page.latestVersion }}/bin/kuma-c
 This example will run Kuma in `standalone` mode for a "flat" deployment, but there are more advanced [deployment modes](../introduction/deployments.md) like "multi-zone".
 
 We suggest adding the `kumactl` executable to your `PATH` so that it's always available in every working directory. Or - alternatively - you can also create link in `/usr/local/bin/` by executing:
-
-```sh
-ln -s kuma-{{ $page.latestVersion }}/bin/kumactl /usr/local/bin/kumactl
-```
+<div class="language-sh">
+<pre><code> ln -s kuma-{{ $page.latestVersion }}/bin/kumactl /usr/local/bin/kumactl </code></pre>
+</div>
 
 ::: tip
 **Note**: By default this will run Kuma with a `memory` [store](../documentation/configuration.md), but for production you have to use a persistent storage like PostgreSQL by updating the `conf/kuma-cp.conf` file.