Encode utf8 character in print stylesheet

Fixes #742.

assets/stylesheets/global/_print.scss

@@ -29,7 +29,7 @@
   }
 
   ._attribution:last-child:after {
-    content: 'Exported from DevDocs — https://devdocs.io';
+    content: 'Exported from DevDocs \2014  https://devdocs.io';
     display: block;
     margin-top: 1rem;
     font-weight: $bolderFontWeight;