fix(emails): fixed white background in email templates

rhodecode/templates/email_templates/base.mako

@@ -409,8 +409,17 b' text_monospace = "\'Menlo\', \'Liberation M'
             -webkit-border-radius: 2px;
             -moz-border-radius: 2px;
             border-radius: 2px;
+            color: #7E7F7F
+        }
+
+        div.markdown-block code,
+        div.markdown-block pre {
+            background-color: transparent;
+        }
+
+        div.markdown-block #ws,
+        div.markdown-block #message {
             background-color: #FFFFFF;
-            color: #7E7F7F
         }
 
         div.markdown-block code {