[range] corrected undesirable namespace nesting in algorithm/search_n.hpp; fixes #6103

[SVN r82071]

include/boost/range/algorithm/search_n.hpp

@@ -20,8 +20,6 @@
 
 namespace boost
 {
-    namespace range
-    {
 
 namespace range_detail
 {
@@ -235,6 +233,8 @@ namespace range_detail
     }
 } // namespace range_detail
 
+namespace range {
+
 /// \brief template function search
 ///
 /// range-based version of the search std algorithm