remove erase(const_iterator) overload, it should have never existed as const_iterators can't be used to modify the container

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@56116 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/hashmap.h

@@ -679,7 +679,6 @@ public: \
     size_type erase( const key_type& k ) \
         { return CLASSNAME##_wxImplementation_HashTable::erase( k ); } \
     void erase( const iterator& it ) { erase( it->first ); } \
-    void erase( const const_iterator& it ) { erase( it->first ); } \
  \
     /* count() == 0 | 1 */ \
     size_type count( const const_key_type& key ) \