Add code sample for codelens helper

website/playground/new-samples/extending-language-services/codelens-provider-example/sample.js

@@ -0,0 +1,33 @@
+var editor = monaco.editor.create(document.getElementById("container"), {
+    value: "{\n\t\"dependencies\": {\n\t\t\n\t}\n}\n",
+    language: "json"
+});
+
+var commandId = editor.addCommand(0, function() {
+    // services available in `ctx`
+    alert('my command is executing!');
+
+}, '');
+
+monaco.languages.registerCodeLensProvider('json', {
+    provideCodeLenses: function(model, token) {
+        return [
+            {
+                range: {
+                    startLineNumber: 1,
+                    startColumn: 1,
+                    endLineNumber: 2,
+                    endColumn: 1
+                },
+                id: "First Line",
+                command: {
+                    id: commandId,
+                    title: "First Line"
+                }
+            }
+        ];
+    },
+    resolveCodeLens: function(model, codeLens, token) {
+        return codeLens;
+    }
+});