[Pulsar Client Tools]Support generate documentation of pulsar admin cli automatically (#5738)

### Motivation

Currently, the commands on the page http://pulsar.apache.org/docs/en/pulsar-admin/ are all manually added. when the document changes, there are often wrong contents. in order to solve this problem, we expect the commands on this page to be automatically generated. this pr is the first step. If it passes, we will add a new page on the website to show the automatically generated commands later.
diff --git a/tests/integration/src/test/java/org/apache/pulsar/tests/integration/cli/CLITest.java b/tests/integration/src/test/java/org/apache/pulsar/tests/integration/cli/CLITest.java
index c30e2e9..1a40c9d 100644
--- a/tests/integration/src/test/java/org/apache/pulsar/tests/integration/cli/CLITest.java
+++ b/tests/integration/src/test/java/org/apache/pulsar/tests/integration/cli/CLITest.java
@@ -321,4 +321,31 @@
         }
     }
 
+    @Test
+    public void testGenerateDocForModule() throws Exception {
+        String[] moduleNames = {
+                "clusters",
+                "tenants",
+                "brokers",
+                "broker-stats",
+                "namespaces",
+                "topics",
+                "schemas",
+                "bookies",
+                "functions",
+                "ns-isolation-policy",
+                "resource-quotas",
+                "functions",
+                "sources",
+                "sinks"
+        };
+        BrokerContainer container = pulsarCluster.getAnyBroker();
+        for (int i = 0; i < moduleNames.length; i++) {
+            ContainerExecResult result = container.execCmd(
+                    PulsarCluster.ADMIN_SCRIPT,
+                    "documents", "generate", moduleNames[i]);
+            Assert.assertTrue(result.getStdout().contains("------------\n\n# " + moduleNames[i]));
+        }
+    }
+
 }