Minor tweaks to issue template

Includes prompting comment in Markdown

ISSUE_TEMPLATE.md

@@ -1,3 +1,11 @@
-- [ ] I have searched for duplicate or closed issues.
+<!---
+Thanks for contributing to XSS Radar! When raising an issue, we ask that you please complete the template below, describe what you did and what you expected and provide screenshots, if possible.
+--->
+
+## Specifications
+
+- [ ] I have searched for duplicate or closed [issues](https://github.com/bugbountyforum/XSS-Radar/issues).
 - [ ] Operating system and version:
-- [ ] Browser version:
+- [ ] Browser version:
+
+## Issue details