Reword note on output formatting

Author: pradyunsg

.github/ISSUE_TEMPLATE/bug-report.yml

@@ -61,7 +61,13 @@ body:
       description: >-
         Provide the output of the steps above, including the commands
         themselves and pip's output/traceback etc. If you're familiar with
-        Markdown, this block will be rendered as a code block.
+        Markdown, this block will have triple backticks added automatically
+        around it -- you don't have to add them.
+
+        If you want to present output from multiple commands, please present
+        that as a shell session (commands you run get prefixed with `$ `).
+        Please also ensure that the "How to reproduce" section contains matching
+        instructions for reproducing this.
       render: sh-session
 
   - type: checkboxes