Use CSS whitespace rather than padding to indent

Author: dirk

src/librustdoc/html/static/main.css

@@ -306,8 +306,10 @@ nav.sub {
     font-size: 1em;
     position: relative;
 }
-/* Shift "where ..." part of method definition down a line and indent it */
-.content .method .where { display: block; padding-left: 3.75em; }
+/* Shift "where ..." part of method definition down a line */
+.content .method .where { display: block; }
+/* Bit of whitespace to indent it */
+.content .method .where::before { content: '      '; }
 
 .content .methods .docblock { margin-left: 40px; }