added name tags for valid expressions and associated types

[SVN r9189]

more/generic_programming.html

@@ -145,16 +145,18 @@ int main()
     called <b><i>refinement</i></b>.
 
     <ul>
-       <li><b>Valid Expressions</b> are C++ expressions which must compile
-	 successfully for the objects involved in the expression to be
-	 considered <i>models</i> of the concept.
-
-      <li><b>Associated Types</b> are types that are related to the
-	modeling type in that they participate in one or more of the
-	valid expressions. Typically associated types can be accessed
-	either through typedefs nested within a class definition for
-	the modeling type, or they are accessed through a <a
-	href="#traits">traits class</a>.
+       <li><a name="valid_expression"><b>Valid Expressions</b></a> are
+	 C++ expressions which must compile successfully for the
+	 objects involved in the expression to be considered
+	 <i>models</i> of the concept.
+
+      <li><a name="associated_type"><b>Associated Types</b></a> are
+	types that are related to the modeling type in that they
+	participate in one or more of the valid expressions. Typically
+	associated types can be accessed either through typedefs
+	nested within a class definition for the modeling type, or
+	they are accessed through a <a href="#traits">traits
+	class</a>.
 
       <li><b>Invariants</b> are run-time characteristics of the
 	objects that must always be true, that is, the functions involving