fix(feature_request.md): update markdown templating

.github/ISSUE_TEMPLATE/feature_request.md

@@ -7,14 +7,18 @@ assignees: ''
 
 ---
 
-**Is your feature request related to a problem? Please describe.**
+## Is your feature request related to a problem? Please describe
+
 A clear and concise description of what the problem is and what the feature provides.
 
-**Describe the solution you'd like**
+## Describe the solution you'd like
+
 A clear and concise description of what you want to happen.
 
-**Describe alternatives you've considered**
+## Describe alternatives you've considered
+
 A clear and concise description of any alternative solutions or features you've considered.
 
-**Additional context**
+## Additional context
+
 Add any other context or screenshots about the feature request here.