Fix wrong reference to Cassandra in DockerImageNames#couchbase

See gh-26399

spring-boot-project/spring-boot-tools/spring-boot-test-support/src/main/java/org/springframework/boot/testsupport/testcontainers/DockerImageNames.java

@@ -50,8 +50,8 @@ public final class DockerImageNames {
 	}
 
 	/**
-	 * Return a {@link DockerImageName} suitable for running Cassandra.
-	 * @return a docker image name for running cassandra
+	 * Return a {@link DockerImageName} suitable for running Couchbase.
+	 * @return a docker image name for running couchbase
 	 */
 	public static DockerImageName couchbase() {
 		return DockerImageName.parse("couchbase/server").withTag(COUCHBASE_VERSION);