Update raspberrypi.md

Author: dceejay

docs/getting-started/raspberrypi.md

@@ -25,7 +25,7 @@ to review the contents of the script first, you can view it [on Github](https://
 bash <(curl -sL https://raw.githubusercontent.com/node-red/linux-installers/master/deb/update-nodejs-and-nodered)
 ```
 
-There are extra parameters you can pass to the script. Add ` --help` to the end of the above command to see them.
+There are extra parameters you can pass to the script. Add <code> --help</code> to the end of the above command to see them.
 
 <div class="doc-callout">
 <div style="float: left; margin-right: 10px; margin-bottom: 30px;">