prefer sh to bash in the docs

docs/tutorial/using-selenium-and-webdriver.md

@@ -14,7 +14,7 @@ From [ChromeDriver - WebDriver for Chrome][chrome-driver]:
 for Electron. It is built on top of [WebdriverIO](http://webdriver.io/) and
 has helpers to access Electron APIs in your tests and bundles ChromeDriver.
 
-```bash
+```sh
 $ npm install --save-dev spectron
 ```
 
@@ -57,7 +57,7 @@ a Node package for testing with web driver, we will use it as an example.
 
 First you need to download the `chromedriver` binary, and run it:
 
-```bash
+```sh
 $ npm install electron-chromedriver
 $ ./node_modules/.bin/chromedriver
 Starting ChromeDriver (v2.10.291558) on port 9515
@@ -68,7 +68,7 @@ Remember the port number `9515`, which will be used later
 
 ### 2. Install WebDriverJS
 
-```bash
+```sh
 $ npm install selenium-webdriver
 ```
 
@@ -114,7 +114,7 @@ driver.
 
 First you need to download the `chromedriver` binary, and run it:
 
-```bash
+```sh
 $ npm install electron-chromedriver
 $ ./node_modules/.bin/chromedriver --url-base=wd/hub --port=9515
 Starting ChromeDriver (v2.10.291558) on port 9515
@@ -125,7 +125,7 @@ Remember the port number `9515`, which will be used later
 
 ### 2. Install WebdriverIO
 
-```bash
+```sh
 $ npm install webdriverio
 ```