update the template

Author: SarahAlidoost

.github/ISSUE_TEMPLATE/bug_report.md

@@ -8,4 +8,4 @@ assignees: ''
 ---
 
 **Describe the bug**
-A clear and concise description of what the bug is. If this issue is about a specific episode within a lesson, please provide its link or filename.
+A clear and concise description of what the bug is. If this issue is about a specific episode, please provide its link or filename.

.github/ISSUE_TEMPLATE/lesson_contribution.md

@@ -7,7 +7,7 @@ assignees: ''
 
 ---
 
-**Short description of the diagnostic**
+**Short description of the material**
 Add a short description of the material that you would like to add.
 
 **Branch and pull request**