api docs: Fix syntax for get-user-groups.

This apparently had some sort of rebase conflict issue with the
migration to the nicer syntax for tabs.

templates/zerver/api/get-user-groups.md

@@ -6,31 +6,19 @@ Fetches all of the user groups in the organization.
 
 ## Usage examples
 
-<div class="code-section" markdown="1">
-<ul class="nav">
-<li data-language="python">Python</li>
-<li data-language="curl">curl</li>
-</ul>
-<div class="blocks">
+{start_tabs}
+{tab|python}
 
-<div data-language="curl" markdown="1">
+{generate_code_example(python)|/user_groups:get|example}
+
+{tab|curl}
 
 ``` curl
 curl -X GET {{ api_url }}/v1/user_groups \
     -u BOT_EMAIL_ADDRESS:BOT_API_KEY
 ```
 
-</div>
-
-<div data-language="python" markdown="1">
-
-{generate_code_example(python)|/user_groups:get|example}
-
-</div>
-
-</div>
-
-</div>
+{end_tabs}
 
 ## Arguments