Fixed formatting

CONTRIBUTING.md

@@ -53,7 +53,7 @@ Before submitting a feature or substantial code contribution please discuss it w
 
 Here's a few things you should always do when making changes to the code base:
 
-**Engineering guidelines*
+**Engineering guidelines**
 
 The coding, style, and general engineering guidelines are published on the [Engineering guidelines](https://github.com/aspnet/Home/wiki/Engineering-guidelines) page.