Update Advanced-Topics-Inline-Styles.md (#1902)

Summary:
**Summary**

Fix the Hello World words which did not rendered properly on the docs site.

**Test Plan**

Before
![image](https://user-images.githubusercontent.com/771989/46931399-8e330d80-d07d-11e8-828d-e74c52724d7a.png)

After
![image](https://user-images.githubusercontent.com/771989/46931423-a3a83780-d07d-11e8-8ada-4468acff26cf.png)
Pull Request resolved: #1902

Differential Revision: D10378437

fbshipit-source-id: e264eadc2dd9fd9e5b660b806e9769a002c08778

Author: alvinthen

docs/Advanced-Topics-Inline-Styles.md

@@ -41,7 +41,7 @@ In essence, our styles are:
 ## Overlapping Styles
 
 Now let's say that we wish to make the middle range of characters italic as well:
-"He_llo **wo**_**rld**". This operation can be performed via the
+He*llo* ***wo*rld**. This operation can be performed via the
 [Modifier](/docs/api-reference-modifier.html) API.
 
 The end result will accommodate the overlap by including `'ITALIC'` in the