Make firstterms bold

[SVN r23394]

doc/html/boostbook.css

@@ -66,6 +66,12 @@ div pre.programlisting, .refsynopsisdiv
    width: 100%;
 }
 
+i.firstterm
+{
+   font-style: normal;
+   font-weight: bold;
+}
+
 @media screen
 {
    a{ color: blue; }