inline DartWrapper concept that did not exist in the original documentation

The page CombinatorialMapItems is now similar to the original one.

Combinatorial_map/doc/Combinatorial_map/Combinatorial_map.txt

@@ -639,19 +639,15 @@ for a handle to the <I>i</I>-attributes (and the const version
 
 The `CombinatorialMapItems` concept defines dart and attribute types
 of a combinatorial map. It contains one inner class named
-\link CombinatorialMapItems::DartWrapper `Dart_wrapper`\endlink,
+\link CombinatorialMapItems::Dart_wrapper `Dart_wrapper`\endlink,
 having one template parameter, `CMap`, a model of
 `CombinatorialMap` concept. The
-\link CombinatorialMapItems::DartWrapper `Dart_wrapper<CMap>`\endlink
+\link CombinatorialMapItems::Dart_wrapper `Dart_wrapper<CMap>`\endlink
 class provides two local types:
-\link CombinatorialMapItems::DartWrapper::Dart `Dart`\endlink
-which must be a model of the `::Dart` concept, and
-\link CombinatorialMapItems::DartWrapper::Attributes `Attributes`\endlink
-which defines the attributes and their types.
+`%Dart` which must be a model of the `::Dart` concept, and
+`%Attributes` which defines the attributes and their types.
 
-The
-\link CombinatorialMapItems::DartWrapper::Attributes `Attributes`\endlink
-tuple must contain at most <I>d</I>+1 types (one for
+The `%Attributes` tuple must contain at most <I>d</I>+1 types (one for
 each possible cell dimension of the combinatorial map). Each type of
 the tuple must be either a model of the `CellAttribute` concept or
 `void`. The first type corresponds to 0-attributes, the second to

Combinatorial_map/doc/Combinatorial_map/Concepts/CombinatorialMapItems.h

@@ -9,7 +9,34 @@ attributes. For that, it defines an inner class template named
 of the `CombinatorialMap` concept. This inner class must define
 two types: `Dart` and `Attributes`.
 
-### Example ###
+\cgalHasModel `CGAL::Combinatorial_map_min_items<d>`
+
+\sa `CombinatorialMap`
+\sa `Dart`
+*/
+class CombinatorialMapItems {
+public:
+
+  /*!
+  The class `%Dart_wrapper<CMap>` must provide:
+
+  - `%Dart_wrapper<CMap>::%Dart`, the type of dart, a model of the `Dart` concept.
+  - `%Dart_wrapper<CMap>::%Attributes` The tuple of attributes, containing at most
+    <I>dimension+1</I> types (one for each possible cell of the combinatorial
+    map). Each type of the tuple must be either a model of the
+    `CellAttribute` concept or `void`.
+    The first type corresponds to 0-attributes,
+    the second to 1-attributes and so on.
+    If the \f$ i^{\mbox{th}}\f$ type in the tuple is `void`,
+    (<I>i</I>-1)-attributes are disabled. Otherwise, (<I>i</I>-1)-attributes are enabled and
+    have the given type. If the size of the tuple is <I>k</I>,
+    with <I>k</I><<I>dimension+1</I>,
+    \f$ \forall\f$<I>i</I>: <I>k</I>\f$ \leq\f$<I>i</I>\f$ \leq\f$<I>dimension</I>,
+    <I>i</I>-attributes are disabled.
+
+  \note It can be implemented using a nested template class.
+  
+  \cgalHeading{Example}
 
   The following examples show two possible models of the
   `CombinatorialMapItems` concept: the first one for a 4D
@@ -40,39 +67,9 @@ struct Exemple_Item_3
   };
   \endcode
   
-\cgalHasModel `CGAL::Combinatorial_map_min_items<d>`
-
-\sa `CombinatorialMap`
-\sa `Dart`
-*/
-class CombinatorialMapItems {
-public:
-
-  /*!
-    \cgalConcept
   */
   template <typename CMap>
-  struct DartWrapper {
-    /*!
-    The type of dart, a model of the `Dart` concept.
-    */
-    typedef Hidden_type Dart;
+  using Dart_wrapper = Hidden_type;
 
-    /*!
-    The tuple of attributes, containing at most
-    <I>dimension+1</I> types (one for each possible cell of the combinatorial
-    map). Each type of the tuple must be either a model of the
-    `CellAttribute` concept or `void`.
-    The first type corresponds to 0-attributes,
-    the second to 1-attributes and so on.
-    If the \f$ i^{\mbox{th}}\f$ type in the tuple is `void`,
-    (<I>i</I>-1)-attributes are disabled. Otherwise, (<I>i</I>-1)-attributes are enabled and
-    have the given type. If the size of the tuple is <I>k</I>,
-    with <I>k</I><<I>dimension+1</I>,
-    \f$ \forall\f$<I>i</I>: <I>k</I>\f$ \leq\f$<I>i</I>\f$ \leq\f$<I>dimension</I>,
-    <I>i</I>-attributes are disabled.
-    */
-    typedef Hidden_type Attributes;
-  };
 }; /* end #CombinatorialMapItems */