Adjusted feature request template for easier management

- Automatically assigns **feature request** label 
- Enclosed extra instructions for each section in HTML comments, so they're visible when editing but disappear upon submission.

.github/ISSUE_TEMPLATE/feature_request.md

@@ -1,17 +1,20 @@
 ---
 name: Feature request
 about: Suggest an idea for this project
-
+labels: 'feature request'
 ---
 
 **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 [...]
+<!-- A clear and concise description of what the problem is. Ex. I'm always frustrated when [...] -->
+
 
 **Describe the solution you'd like**
-A clear and concise description of what you want to happen.
+<!-- A clear and concise description of what you want to happen. -->
+
 
 **Describe alternatives you've considered (optional)**
-A clear and concise description of any alternative solutions or features you've considered.
+<!-- A clear and concise description of any alternative solutions or features you've considered. -->
+
 
 **Additional context (optional)**
-Add any other context or screenshots about the feature request here.
+<!-- Add any other context or screenshots about the feature request here. -->