Add javadoc <p> tags

Author: aherbert

src/main/java/org/apache/commons/codec/binary/Base16.java

@@ -25,15 +25,17 @@
  * <p>
  * This class is thread-safe.
  * </p>
- *
+ * <p>
  * This implementation strictly follows RFC 4648, and as such unlike
  * the {@link Base32} and {@link Base64} implementations,
  * it does not ignore invalid alphabet characters or whitespace,
  * neither does it offer chunking or padding characters.
- *
+ * </p>
+ * <p>
  * The only additional feature above those specified in RFC 4648
  * is support for working with a lower-case alphabet in addition
  * to the default upper-case alphabet.
+ * </p>
  *
  * @see <a href="https://tools.ietf.org/html/rfc4648#section-8">RFC 4648 - 8. Base 16 Encoding</a>
  *