Update bug_report.md

Author: drobnyjt

.github/ISSUE_TEMPLATE/bug_report.md

@@ -1,5 +1,5 @@
 ---
-name: Bug report (affects results)
+name: Bug report (major)
 about: Report a problem with the code
 title: "[bug]"
 labels: bug
@@ -8,7 +8,7 @@ assignees: ''
 ---
 
 **Description**
-A complete, clear, and concise description of what the bug is. 
+A complete, clear, and concise description of what the bug is. A major bug is one that has a significant effect on scientific results and is likely to occur for typical use-cases. All other bugs are minor bugs.
 
 **Location**
 Specify the relevant line number(s), definition(s), etc.