fix checkstyle

Author: wangmingliang-ms

PluginsAndFeatures/azure-toolkit-for-intellij/azure-sdk-reference-book/src/main/java/com/microsoft/azure/toolkit/intellij/azuresdk/referencebook/AzureSdkArtifactDetailPanel.java

@@ -1,3 +1,8 @@
+/*
+ * Copyright (c) Microsoft Corporation. All rights reserved.
+ * Licensed under the MIT License. See License.txt in the project root for license information.
+ */
+
 package com.microsoft.azure.toolkit.intellij.azuresdk.referencebook;
 
 import com.google.common.collect.ImmutableMap;
@@ -70,14 +75,14 @@ private DropDownLink<String> buildVersionSelector() {
         if (StringUtils.isNotBlank(artifact.getVersionPreview())) {
             versions.add(artifact.getVersionPreview());
         }
-        final DropDownLink<String> version = new DropDownLink<>(versions.get(0), versions, (String v) -> {
+        final DropDownLink<String> versionSelector = new DropDownLink<>(versions.get(0), versions, (String v) -> {
             if (this.artifactId.isSelected()) {
                 this.setLinks(this.artifact.getLinks(v));
                 this.onArtifactOrVersionSelected.accept(this.artifact, this.version.getSelectedItem());
             }
         }, true);
-        version.setForeground(JBColor.BLACK);
-        return version;
+        versionSelector.setForeground(JBColor.BLACK);
+        return versionSelector;
     }
 
     public void setSelected(boolean selected) {