Commit message blocks

#### What does this MR do?
* Wraps code commit message blocks
* Consolidates similar shades of gray (cc @cperessini @tauriedavis)

Related to #20831 

#### Screenshots (if relevant)
Before:  
![Screen_Shot_2016-08-19_at_10.41.07_AM](/uploads/4529d178123e18b0aad35a252061902b/Screen_Shot_2016-08-19_at_10.41.07_AM.png)
After: 
![Screen_Shot_2016-08-19_at_10.40.42_AM](/uploads/499818f360e7c3cd9d31bc335cae1a82/Screen_Shot_2016-08-19_at_10.40.42_AM.png)



See merge request !5906