docs: update contrib guide (#539)

* update contrib guide

* fix number

Author: technicallyty

CONTRIBUTING.md

@@ -21,7 +21,10 @@ We appreciate community contributions! To ensure a smooth process, please follow
    - All commits must be [signed](https://docs.github.com/en/authentication/managing-commit-signature-verification/signing-commits).
    - Unsigned commits will be rejected.
 
-3. **Documentation Contributions**
+3. **Conventional Commit PR Titles**
+    - PR titles should use the [conventional commit](https://www.conventionalcommits.org/en/v1.0.0/#summary) format.
+
+4. **Documentation Contributions**
    - We only accept documentation PRs that make **substantial or impactful changes**.
    - Minor typo or style-only fixes in documentation will not be accepted.