.github: update bug report template

Author: tulir

.github/ISSUE_TEMPLATE/bug.md

@@ -5,3 +5,10 @@ about: If something is definitely wrong in the bridge (rather than just a setup
 labels: bug
 
 ---
+
+<!--
+Remember to include relevant logs, the bridge version and any other details.
+
+If you aren't sure what's needed, ask in the Matrix room rather than opening an
+incomplete issue. Issues with insufficient detail will likely just be ignored.
+-->