Highlight changes inside diff lines (#7139).

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@5094 e93f8b46-1217-0410-a6f0-8f06a7374b81

public/stylesheets/application.css

@@ -672,7 +672,9 @@ div.autocomplete ul li span.informal {
 
 /***** Diff *****/
 .diff_out { background: #fcc; }
+.diff_out span { background: #faa; }
 .diff_in { background: #cfc; }
+.diff_in span { background: #afa; }
 
 .text-diff {
 padding: 1em;