improve R syntax highlight (#1605)

Author: randy3k

.vscode/tasks.json

@@ -35,16 +35,14 @@
       "script": "compile",
       "problemMatcher": "$tsc"
     },
-    {
+		{
       "type": "npm",
       "script": "watch",
-      "problemMatcher": "$tsc-watch",
-      "isBackground": true,
-      "presentation": {
-        "reveal": "never"
-      },
-      "group": "build"
-    },
+      "group": "build",
+      // install https://marketplace.visualstudio.com/items?itemName=eamodio.tsl-problem-matcher
+      "problemMatcher": ["$ts-webpack-watch"],
+      "isBackground": true
+		},
     {
       "type": "npm",
       "script": "watchHelp",