fix prettier

Author: jonassorgenfrei

docs/howto/customize-link-protocols.md

@@ -15,6 +15,7 @@ Links using these protocols are opened directly by the system.
 All other protocols are considered potentially unsafe and are therefore opened indirectly—through a local HTML file—in your default web browser.
 
 ## Extending the Whitelisted Protocols
+
 It is possible to customize the list of whitelisted protocols by editing the `settings.json` file located at: `userdata/Zulip/config/settings.json`
 
 To add or modify the list, the `whitelistedProtocols` key can be updated. For example: