Fix documentation for trim_all and trim_fill

include/boost/algorithm/string/trim_all.hpp

@@ -108,7 +108,6 @@ namespace boost {
 
             \param Input An input sequence
             \param Loc A locale used for 'space' classification
-            \return A trimmed copy of the input
         */
         template<typename SequenceT>
         inline void trim_all(SequenceT& Input, const std::locale& Loc =std::locale())
@@ -191,7 +190,6 @@ namespace boost {
             \param Input An input sequence
             \param Fill A string used to fill the inner spaces
             \param Loc A locale used for 'space' classification
-            \return A trimmed copy of the input
         */
         template<typename SequenceT, typename RangeT>
         inline void trim_fill(SequenceT& Input, const RangeT& Fill, const std::locale& Loc =std::locale())