Fix typo

Close mmistakes#2911

Author: mmistakes

docs/_docs/05-configuration.md

@@ -131,7 +131,7 @@ You also have the option of customizing the separation character used in SEO-fri
 
 _Example:_ `title_separator: "|"` would produce page titles like `Sample Page | My Awesome Site`.
 
-**Note:** Long site titles have been known to break the masthead layout. Avoid adding a long "tagline" to the title prevent this from happening eg. `My Awesome Site is the Best Because I Say So".
+**Note:** Long site titles have been known to break the masthead layout. Avoid adding a long "tagline" to the title prevent this from happening eg. `My Awesome Site is the Best Because I Say So`.
 {: .notice--warning}
 
 ### Site subtitle