Update feature_request.md

Author: mrdoob

.github/ISSUE_TEMPLATE/feature_request.md

@@ -7,6 +7,8 @@ assignees: ''
 
 ---
 
+<!-- Ignoring this template may result in your feature request getting deleted -->
+
 **Is your feature request related to a problem? Please describe.**
 
 A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]