change code block comments

Author: ckoegel

.github/ISSUE_TEMPLATE/bug_report.md

@@ -24,13 +24,13 @@ labels: 'bug'
 ### Sample Code Snippet
 <!-- Please provide a code snippet that produces or is relevant to the bug. -->
 ```ruby
-# Please provide a code snippet that produces or is relevant to the bug.
+# Sample Code Snippet
 ```
 
 ### Stack Trace
 <!-- Please provide the stack trace that shows the bug. -->
 ```shell
-# Please provide the stack trace that shows the bug.
+# Stack Trace
 ```
 
 ### Expected Behavior