Improve javadoc for some addons (#15701)

Signed-off-by: Holger Friedrich <mail@holger-friedrich.de>

bundles/org.openhab.binding.upnpcontrol/src/main/java/org/openhab/binding/upnpcontrol/internal/util/StringUtils.java

@@ -25,11 +25,16 @@ public class StringUtils {
     /**
      * Simple method to escape XML special characters in String.
      * There are five XML Special characters which needs to be escaped :
+     *
+     * <pre>
+     * {@code
      * & - &amp;
      * < - &lt;
      * > - &gt;
      * " - &quot;
      * ' - &apos;
+     * }
+     * </pre>
      */
     public static String escapeXml(String xml) {
         xml = xml.replace("&", "&amp;");
@@ -43,11 +48,16 @@ public class StringUtils {
     /**
      * Simple method to un escape XML special characters in String.
      * There are five XML Special characters which needs to be escaped :
+     *
+     * <pre>
+     * {@code
      * & - &amp;
      * < - &lt;
      * > - &gt;
      * " - &quot;
      * ' - &apos;
+     * }
+     * </pre>
      */
     public static String unEscapeXml(String xml) {
         xml = xml.replace("&amp;", "&");

bundles/org.openhab.binding.upnpcontrol/src/main/java/org/openhab/binding/upnpcontrol/internal/util/UpnpProtocolMatcher.java

@@ -36,7 +36,7 @@ public final class UpnpProtocolMatcher {
      * Test if an UPnP protocol matches the object class. This method is used to filter resources for the primary
      * resource.
      *
-     * @param protocol format: <protocol>:<network>:<contentFormat>:<additionalInfo>
+     * @param protocol format: {@code <protocol>:<network>:<contentFormat>:<additionalInfo>}
      *            e.g. http-get:*:audio/mpeg:*
      * @param objectClass e.g. object.item.audioItem.musicTrack
      * @return true if protocol matches objectClass
@@ -71,7 +71,7 @@ public final class UpnpProtocolMatcher {
      * Ignore vendor specific additionalInfo part in UPnP protocol string.
      * Do all comparisons in lower case.
      *
-     * @param protocol format: <protocol>:<network>:<contentFormat>:<additionalInfo>
+     * @param protocol format: {@code <protocol>:<network>:<contentFormat>:<additionalInfo>}
      * @param protocolSet
      * @return true if protocol in protocolSet
      */