chore: Improve PR template

.github/PULL_REQUEST_TEMPLATE.md

@@ -15,19 +15,22 @@ Please include a summary of the changes.
 Explain the reason for the changes and any context that might be helpful for the reviewer.
 -->
 
-1. summary of changes
+1. Summary of changes
 
 - **What is the purpose of this PR?**
+  - (if applicable)
 - **What problem does it solve?**
+  - (if applicable)
 - **Are there any breaking changes or backwards compatibility issues?**
+  - (if applicable)
 
 ### Related Issue
 
 <!--
 If this PR addresses an existing issue, please provide a reference to it.
 -->
 
-- Closes #123
+- Closes #Number(if applicable)
 
 ### Type of Change
 
@@ -50,7 +53,7 @@ Please describe the tests that you ran to verify your changes.
 Include any details about the environment or specific configurations used during testing.
 -->
 
-- [ ] I have run unit tests
+- [ ] I have run unit tests(if applicable)
 
 ### Checklist
 
@@ -59,13 +62,15 @@ Please check the following before submitting the PR.
 -->
 
 - [ ] I have read and followed the guidelines in `CONTRIBUTING.md`
-- [ ] I have already updated the related templates accordingly (if applicable)
-- [ ] I have written or updated relevant documentation (if applicable)
-- [ ] I have added or updated tests to cover my changes (if applicable)
+- [ ] I have already updated the related templates accordingly(if applicable)
+- [ ] I have written or updated relevant documentation(if applicable)
+- [ ] I have added or updated tests to cover my changes(if applicable)
 - [ ] I have reviewed my code for any potential issues
 
 ### Additional Notes
 
 <!--
 Any additional information.
 -->
+
+(if applicable)