Self-closing elements are not allowed on Java 11

Author: garydgregory

src/main/javadoc/overview.html

@@ -99,7 +99,7 @@ <h1>Digest Encoders</h1>
 					href="https://en.wikipedia.org/wiki/Key_derivation_function">key
 						derivation function</a>, and can be used as the basis for a <a
 					href="https://en.wikipedia.org/wiki/Cryptographically-secure_pseudorandom_number_generator">
-						cryptographically-secure pseudorandom number generator</a>. <br /> <strong>WARNING:</strong>
+						cryptographically-secure pseudorandom number generator</a>.  <strong>WARNING:</strong>
 					Blake3 is <em>not</em> a password hashing algorithm! An algorithm
 					such as <a href="https://github.com/P-H-C/phc-winner-argon2">Argon2</a>
 					is more appropriate for password hashing.
@@ -127,7 +127,7 @@ <h1>Digest Encoders</h1>
 				</td>
 				<td>Simplifies common <a
 					href="https://docs.oracle.com/javase/6/docs/api/javax/crypto/Mac.html">Mac</a>
-					tasks. <br /> <strong>Note:</strong> Not all JCE implementations
+					tasks.  <strong>Note:</strong> Not all JCE implementations
 					support all algorithms. If not supported, an
 					IllegalArgumentException is thrown.
 				</td>