comma is necessary (#1402)

Author: salmanmkc

articles/bot-service-overview-introduction.md

@@ -64,7 +64,7 @@ You also have access to a variety of [samples](https://github.com/microsoft/botb
 ### Test 
 Bots are complex apps, with a lot of different parts working together. Like any other complex app, this can lead to some interesting bugs or cause your bot to behave differently than expected. Before publishing, test your bot. We provide several ways to test bots before they are released for use:
 
-- Test your bot locally with the [emulator](bot-service-debug-emulator.md). The Bot Framework Emulator is a stand-alone app that not only provides a chat interface, but also debugging and interrogation tools to help understand how and why your bot does what it does.  The emulator can be run locally alongside your in-development bot application. 
+- Test your bot locally with the [emulator](bot-service-debug-emulator.md). The Bot Framework Emulator is a stand-alone app that not only provides a chat interface but also debugging and interrogation tools to help understand how and why your bot does what it does.  The emulator can be run locally alongside your in-development bot application. 
 
 - Test your bot on the [web](bot-service-manage-test-webchat.md). Once configured through the Azure portal your bot can also be reached through a web chat interface. The web chat interface is a great way to grant access to your bot to testers and other people who do not have direct access to the bot's running code.