doxygen: put subscriptor function into group

These functions now appear (see #10914) in each derived class like
SparsityPattern. Provide a heading for these functions.

diff --git a/include/deal.II/base/subscriptor.h b/include/deal.II/base/subscriptor.h
index 363338a1da0968cc6f205f54c1cdd9807c49d8de..7f136b4e0bd3ed40c1f810f357a5fd4af33c01bc 100644 (file)
--- a/include/deal.II/base/subscriptor.h
+++ b/include/deal.II/base/subscriptor.h
@@ -102,6 +102,14 @@ public:
   Subscriptor &
   operator=(Subscriptor &&) noexcept;
 
+  /**
+   * @name Subscriptor functionality
+   *
+   * Classes derived from Subscriptor provide a facility to subscribe to this
+   * object. This is mostly used by the SmartPointer class.
+   */
+  // @{
+
   /**
    * Subscribes a user of the object by storing the pointer @p validity. The
    * subscriber may be identified by text supplied as @p identifier.
@@ -141,6 +149,8 @@ public:
   void
   list_subscribers() const;
 
+  // @}
+
   /**
    * @addtogroup Exceptions
    * @{