[DOCS] update pull request template (#1568)

* docs: update pull request template with module checklist and refined change types

- Add "Module" section with checkboxes for various project components
- Simplify "Type of Change" section by removing nested structure
- Add "Refactor" as a new change type option
---------

Signed-off-by: staryxchen <staryxchen@tencent.com>
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

.github/pull_request_template.md

@@ -2,21 +2,28 @@
 
 <!-- A clear and concise description of the changes. Link to any relevant issues. -->
 
+## Module
+
+- [ ] Transfer Engine (`mooncake-transfer-engine`)
+- [ ] Mooncake Store (`mooncake-store`)
+- [ ] Mooncake EP (`mooncake-ep`)
+- [ ] Integration (`mooncake-integration`)
+- [ ] P2P Store (`mooncake-p2p-store`)
+- [ ] Python Wheel (`mooncake-wheel`)
+- [ ] PyTorch Backend (`mooncake-pg`)
+- [ ] Mooncake RL (`mooncake-rl`)
+- [ ] CI/CD
+- [ ] Docs
+- [ ] Other
+
 ## Type of Change
 
-* Types
-  - [ ] Bug fix
-  - [ ] New feature
-    - [ ] Transfer Engine
-    - [ ] Mooncake Store
-    - [ ] Mooncake EP
-    - [ ] Integration
-    - [ ] P2P Store
-    - [ ] Python Wheel
-  - [ ] Breaking change
-  - [ ] CI/CD
-  - [ ] Documentation update
-  - [ ] Other
+- [ ] Bug fix
+- [ ] New feature
+- [ ] Refactor
+- [ ] Breaking change
+- [ ] Documentation update
+- [ ] Other
 
 ## How Has This Been Tested?