Add default element-link styling.

--HG--
extra : rebase_source : 52a48dfc69969320c924c869a18dfe91cc80a0b4

Author: tabatkins

default.css

@@ -213,6 +213,11 @@ code.xml { color: #600 }	/* inline XML */
 [data-link-type].production::before,
 [data-link-type].production::after { content: ""; }
 
+/* Element-type link styling */
+[data-link-type=element] { font-family: monospace; }
+[data-link-type=element]::before { content: "<" }
+[data-link-type=element]::after { content: ">" }
+
 dfn { font-weight: bolder; }
 a > i { font-style: normal; } /* Instance of term */