fix(styles) restore wrapping of long text in pre blocks (#6377)

Author: scottohara

src/style/_markdown.scss

@@ -8,6 +8,7 @@
     white-space: pre-wrap;
     background: none;
     padding: 0px;
+    overflow-wrap: break-word;
   }
 
   code {
@@ -23,4 +24,4 @@
   pre > code {
     display: block;
   }
-}
+}