Mark members in ParticleAccessor as 'private'.

This class is not meant to be derived from, and I *think* that the reason why
these members were only 'protected' and not 'private' is to somehow indicate
that these are members that 'friend' classes might access. But that is too
complicated an interpretation. Let's just make everything 'private', as
usual.

diff --git a/include/deal.II/particles/particle_accessor.h b/include/deal.II/particles/particle_accessor.h
index cd9d07d1638b0719b2b673a318e685e1b87d156b..401ae71ec396c5d1ba7aeb234cb48822904fd258 100644 (file)
--- a/include/deal.II/particles/particle_accessor.h
+++ b/include/deal.II/particles/particle_accessor.h
@@ -239,7 +239,7 @@ namespace Particles
     bool
     operator==(const ParticleAccessor<dim, spacedim> &other) const;
 
-  protected:
+  private:
     /**
      * Construct an invalid accessor. Such an object is not usable.
      */
@@ -247,7 +247,7 @@ namespace Particles
 
     /**
      * Construct an accessor from a reference to a map and an iterator to the
-     * map. This constructor is protected so that it can only be accessed by
+     * map. This constructor is `private` so that it can only be accessed by
      * friend classes.
      */
     ParticleAccessor(