Fix DocumentID Formatting

Author: daymxn

firebase-firestore/src/main/java/com/google/firebase/firestore/DocumentId.java

@@ -24,7 +24,8 @@
  * the POJO is created from a Cloud Firestore document (for example, via {@link
  * DocumentSnapshot#toObject(Class)}).
  *
- * <p>Any of the following will throw a runtime exception:</p>
+ * <p>Any of the following will throw a runtime exception:
+ *
  * <ul>
  *   <li>This annotation is applied to a property of a type other than String or {@link
  *       DocumentReference}.