Fix "liquid" warning on logging plugins page
Noticed this warning in the documentation CI:
Liquid Warning: Liquid syntax error (line 210): Expected end_of_string but found id in "{{ log stream }}" in engine/extend/plugins_logging.md
@@ -213,7 +213,7 @@ to determine what set of logs to read.
**Response**:
```
-{{ log stream }}
+{% raw %}{{ log stream }}{% endraw %}
```
The response should be the encoded log message using the same format as the
