Document another way to get back nashorn on jdk 15

xdocs/changes.xml

@@ -334,7 +334,28 @@ export JVM_ARGS="-Dnashorn.args=--no-deprecation-warning"
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-With Java 15 the JavaScript implementation <a href="https://openjdk.java.net/jeps/372">Nashorn has been removed</a>. To add back a JSR-223 compatible JavaScript engine, copy <a href="https://github.com/mozilla/rhino/releases/download/Rhino1_7_13_Release/rhino-engine-1.7.13.jar">rhino-engine-1.7.13.jar</a> into <code>$JMETER_HOME/lib/ext</code>.
+With Java 15 the JavaScript implementation <a href="https://openjdk.java.net/jeps/372">Nashorn has been removed</a>. To add back a JSR-223 compatible JavaScript engine you have two options:
+  <dl>
+    <dt>Use Mozilla Rhino</dt>
+    <dd>Copy <a href="https://github.com/mozilla/rhino/releases/download/Rhino1_7_13_Release/rhino-engine-1.7.13.jar">rhino-engine-1.7.13.jar</a> into <code>$JMETER_HOME/lib/ext</code>.</dd>
+    <dt>Use OpenJDK Nashorn</dt>
+    <dd>
+      The OpenJDK Nashorn implementation comes as a module. To use it, you will have to download it and add it to the module path. A hacky way to download the version 15.0 and its dependencies and set the module path is outlined below:
+      <source>
+mkdir lib/modules
+pushd lib/modules
+wget https://repo1.maven.org/maven2/org/openjdk/nashorn/nashorn-core/15.0/nashorn-core-15.0.jar
+wget https://repo1.maven.org/maven2/org/ow2/asm/asm/9.0/asm-9.0.jar
+wget https://repo1.maven.org/maven2/org/ow2/asm/asm-commons/9.0/asm-commons-9.0.jar
+wget https://repo1.maven.org/maven2/org/ow2/asm/asm-util/9.0/asm-util-9.0.jar
+wget https://repo1.maven.org/maven2/org/ow2/asm/asm-tree/9.0/asm-tree-9.0.jar
+wget https://repo1.maven.org/maven2/org/ow2/asm/asm-analysis/9.0/asm-analysis-9.0.jar
+popd
+export JVM_ARGS="--modulepath $PWD/lib/modules"
+./bin/jmeter
+      </source>
+    </dd>
+  </dl>
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