Fixes #5924 - Javadoc build triggers maven error

Fixed javadoc generation error.
Apparently, this is caused by a doxia dependency of asciidoctor-maven-plugin
that transitively pulls in Apache HttpClient, but at an older version
that causes this error:

Exception in thread “main” java.lang.NoSuchMethodError: ‘org.apache.http.HttpHost org.apache.http.client.utils.URIUtils.extractHost(java.net.URI)’

Adding Apache HttpClient as an explicit dependency of the asciidoctor-maven-plugin
works around the issue.

Co-authored-by: olivier lamy <oliver.lamy@gmail.com>
Signed-off-by: Simone Bordet <simone.bordet@gmail.com>

documentation/jetty-documentation/pom.xml

@@ -27,6 +27,16 @@
             <artifactId>jetty-asciidoctor-extensions</artifactId>
             <version>${project.version}</version>
           </dependency>
+          <dependency>
+            <groupId>org.apache.httpcomponents</groupId>
+            <artifactId>httpcore</artifactId>
+            <version>4.4.13</version>
+          </dependency>
+          <dependency>
+            <groupId>org.apache.httpcomponents</groupId>
+            <artifactId>httpclient</artifactId>
+            <version>4.5.13</version>
+          </dependency>
         </dependencies>
         <configuration>
           <backend>html5</backend>

pom.xml

@@ -1319,11 +1319,9 @@
     </profile>
     <profile>
       <id>eclipse-release</id>
-      <!-- Disabled Temporarily: see Issue #5942
       <modules>
         <module>javadoc</module>
       </modules>
-      -->
       <build>
         <plugins>
           <plugin>
@@ -1396,11 +1394,9 @@
         <spotbugs.skip>false</spotbugs.skip>
         <spotbugs.onlyAnalyze>org.eclipse.jetty.*</spotbugs.onlyAnalyze>
       </properties>
-      <!-- Disabled Temporarily: see Issue #5942
       <modules>
         <module>javadoc</module>
       </modules>
-      -->
       <build>
         <pluginManagement>
           <plugins>