Restore float:left style for note lists

Unlike the original note list styles, this version sets the line-height
for all `dt` elements to be the same as the `p` elements contained
inside the `dd`, so that the second line has the same indentation as all
subsequent lines.

Author: nevans

lib/rdoc/generator/template/darkfish/css/rdoc.css

@@ -469,9 +469,15 @@ main dl {
 }
 
 main dt {
+  line-height: 1.5; /* matches `main p` */
   font-weight: bold;
 }
 
+main dl.note-list dt {
+  margin-right: 1em;
+  float: left;
+}
+
 main dd {
   margin: 0 0 1em 1em;
 }