Amend #344, correct spacing on line-numbering (#382)

Closes #381

Author: skirpichev

sass/_theme_rst.sass

@@ -19,7 +19,7 @@
     max-width: 100%
     height: auto !important
 
-  .highlight > pre
+  .highlight > pre, .linenodiv > pre
     line-height: normal
 
   div.figure