fixed the annotation tooltip line height so it is the same in studio and the lms.

common/lib/xmodule/xmodule/css/annotatable/display.scss

@@ -144,6 +144,7 @@ $body-font-size: em(14);
       margin: 0px 0px 10px 0;
       max-height: 225px;
       overflow: auto;
+      line-height: normal;
     }
     .annotatable-reply {
       display: block;