Update node-sass-chokidar docs (facebook#4205)

* Removes Chokidar Recursive Flag

According to the changelog it is not necessary anymore as it doesn't do anything.

* Removes initial build on SCSS watch

Chokidar now does this on it's own.

* Removes sass watch recursive, default include-path

as proposed by @michaelwayman

* Removes another left-over build-css

Author: originell

packages/react-scripts/template/README.md

@@ -621,7 +621,7 @@ Then in `package.json`, add the following lines to `scripts`:
 ```diff
    "scripts": {
 +    "build-css": "node-sass-chokidar src/ -o src/",
-+    "watch-css": "npm run build-css && node-sass-chokidar src/ -o src/ --watch --recursive",
++    "watch-css": "node-sass-chokidar src/ -o src/ --watch",
      "start": "react-scripts start",
      "build": "react-scripts build",
      "test": "react-scripts test --env=jsdom",
@@ -636,8 +636,8 @@ To share variables between Sass files, you can use Sass imports. For example, `s
 To enable importing files without using relative paths, you can add the  `--include-path` option to the command in `package.json`.
 
 ```
-"build-css": "node-sass-chokidar --include-path ./src --include-path ./node_modules src/ -o src/",
-"watch-css": "npm run build-css && node-sass-chokidar --include-path ./src --include-path ./node_modules src/ -o src/ --watch --recursive",
+"build-css": "node-sass-chokidar --include-path ./node_modules src/ -o src/",
+"watch-css": "node-sass-chokidar --include-path ./node_modules src/ -o src/ --watch",
 ```
 
 This will allow you to do imports like