Offset blockquotes with margin bar

Similar to many email programs, offset a blockquoted region with a bar
on the left margin.  Color the background so it also stands out from
the main text.

Change-Id: Icba38163872f69ea49dacd2ce6207ee1d526a1ad

gitiles-servlet/src/main/resources/com/google/gitiles/static/doc.css

diff --git a/gitiles-servlet/src/main/resources/com/google/gitiles/static/doc.css b/gitiles-servlet/src/main/resources/com/google/gitiles/static/doc.css
index d10b403..3006d29 100644
--- a/gitiles-servlet/src/main/resources/com/google/gitiles/static/doc.css
+++ b/gitiles-servlet/src/main/resources/com/google/gitiles/static/doc.css
@@ -147,6 +147,11 @@
 .doc p {
   margin: 10px 0;
 }
+.doc blockquote {
+  background-color: #fffde7;
+  border-left: 2px solid #fab700;
+  padding: 2px 10px 2px 10px;
+}
 .doc pre {
   padding: 12px;
   font-size: 10pt;