docs: minor Design Principles fixes for Android Design

Change-Id: I3d69c5fd420e7e6a7d70ebf4a65179af23a70859

Author: romannurik

docs/html/design/get-started/principles.html

@@ -148,7 +148,7 @@ <h4>Real objects are more fun than buttons and menus</h4>
 
 <h4>Let me make it mine</h4>
 <p>People love to add personal touches because it helps them feel at home and in control. Provide
-sensible, beautiful defaults, but also consider fun, optional customizations that don’t hinder
+sensible, beautiful defaults, but also consider fun, optional customizations that don't hinder
 primary tasks.</p>
 
   </div>