changeset comments: attempt to highlight the linked comment

This makes it slightly less confusing to follow a notification link to a page
with a lot of comments.

It is ugly, it seems like it doesn't work reliably, and the fixed top menu makes
target navigation unusable in general...

rhodecode/public/css/style.css

@@ -4874,3 +4874,8 b' table.code-difftable .code pre{'
 	background-color: inherit !important;
 	
 }
+
+div:target {
+	border: solid 2px #ee0 !important;
+	margin: -2px;
+}