Add code action section into walkthrough (#1372)

Author: jdneo

package.json

@@ -115,6 +115,15 @@
             },
             "when": "!java:projectManagerActivated || workspaceFolderCount == 0"
           },
+          {
+            "id": "java.codeActions",
+            "title": "View code actions and source actions",
+            "description": "%walkthrough.java.codeActions%",
+            "media": {
+              "svg": "walkthrough/codeAction.svg",
+              "altText": "Code actions and source actions"
+            }
+          },
           {
             "id": "java.debugAndTest",
             "title": "Launch, debug and test",

package.nls.json

@@ -7,6 +7,8 @@
 
     "walkthrough.java.projects.inactive": "Java Project Explorer helps you to manage your projects and dependencies. Create a new project or open an existing folder to see the full features.\n[Open Command Palette](command:workbench.action.quickOpen?%22>java%22)\n__Try searching for 'Create Java Project' or 'Open Folder'__",
 
+    "walkthrough.java.codeActions": "Find available actions for your code in the editor:\n  - Open the right-click menu then select \"Refactor...\" or \"Source Action...\".\n  - Click on the light bulb💡.",
+
     "walkthrough.java.debugAndTest":"Run and debug your application using the debugger. [Learn More...](https://aka.ms/java-walkthrough-debug)\nThe [Testing Explorer](command:workbench.view.testing.focus) allows you to view, run and manage all test cases in your project. [Learn More...](https://aka.ms/java-walkthrough-test)\n[Show Run and Debug View](command:workbench.view.debug)",
 
     "walkthrough.java.extensions": "Install extensions to support additional frameworks such as Spring Boot, Application Servers, key mappings and so on.\n[Browse Recommended Extensions](command:toSide:java.extGuide)",