Fixed formatting issue in ".gitlab/issue_templates/Bug.md".

.gitlab/issue_templates/Bug.md

@@ -27,13 +27,16 @@ How can you reproduce the issue?
 
 Please, use code blocks (backticks) and if it is much text, encapsulate the text in `<details>` tag:
 
+```
+A short
+code block
+```
+
 <details>
-<summary>Expand file xy...</summary>
+<summary>A long code block...</summary>
 <pre>
-```
 Line 1 of log file xy`
 Line 2 of log file xy`
-```
 </pre>
 </details>