Update PR template with item to tag docs team (#6766)

Author: elle-j

.github/pull_request_template.md

@@ -14,3 +14,4 @@ This closes # ??? <!-- link to an existing issue -->
 * [ ] 📦 Updated internal package version in consuming `package.json`s (if updating internal packages)
 * [ ] 📱 Check the React Native/other sample apps work if necessary
 * [ ] 💥 `Breaking` label has been applied or is not necessary
+* [ ] 🔔 Mention `@realm/devdocs` if documentation changes are needed